Web services enable the new generation of Internet-based applications. These services support application-to-application Internet communication--that is, applications at different network locations can be integrated to function as if they were part of a single, large software system. Examples of applications made possible by Web services include automated business transactions and direct (nonbrowser) desktop and handheld device access to reservations, stock trading, and order-tracking systems.

Several key standards have emerged that together form the foundation for Web services: XML (Extensible Markup Language), WSDL (Web Services Definition Language), SOAP (Simple Object Access Protocol), and UDDI (Universal Description, Discovery, and Integration). In addition, ebXML (Electronic Business XML) has been specified to facilitate automated business process integration among trading partners.

This book introduces the main ideas and concepts behind core and extended Web services' technologies and provides developers with a primer for each of the major technologies that have emerged in this space. In addition, Understanding Web Services summarizes the major architectural approaches to Web services, examines the role of Web services within the .NET and J2EE communities, and provides information about major product offerings from BEA, Hewlett-Packard, IBM, IONA, Microsoft, Oracle, Sun Microsystems, and others.

Key topics include:

• XML facilities for structuring and serializing data
• How WSDL maps services onto communication protocols and transports
• WSDL support for RPC-oriented and document-oriented interactions
• SOAP's required and optional elements
• Message processing and the role of intermediaries in SOAP
• UDDI data formats and APIs
• How ebXML offers an alternative to Web services that supports reliable messaging, security, and trading-partner negotiations

With Understanding Web Services, you will be well informed and well positioned to participate in this vast, emerging marketplace.

Eric Newcomer is chief technical officer at IONA (http://www.iona.com), an independent provider of e-business platforms for Web services integration. As a member of the World Wide Web Consortium (W3C), the organization responsible for establishing Web standards, he participates in the XML Protocols and Web Services Architecture Working Groups. He is also IONA's representative to UDDI.org and has been active in Web services since early 2000. He is the coauthor of the highly acclaimed Principles of Transaction Processing (Morgan Kaufmann, 1997), as well as numerous journal articles, chapters, and conference reports.

I first encountered XML as an integration technology in early 1998 during a visit to KPN Telecom in the Netherlands. The company was asking for proposals to help it develop an enterprise integration architecture based on the hub and spoke model, using XML as the canonical message format that would tie together the company's thousands of systems and hundreds of programming languages. My employer at the time, Compaq (Digital), did not win the project, but the controversial idea of using XML in a data-independent integration layer stuck with me. Now Web services are fulfilling that promise for everyone.

I joined IONA in the fall of 1999 and among other things soon began chairing the Object Management Group submitter's team drafting the XML Value specification, mapping XML to CORBA. In early 2000, I got involved in the new effort Microsoft was leading to define a distributed computing protocol for the Internet: SOAP. Previous attempts to promote the CORBA protocol had failed by then, and the W3C's own attempt, HTTP-NG, had also fallen flat. But the idea of serializing XML over HTTP seemed to hold promise for a solution.

IONA formally joined the SOAP effort in March 2000, before IBM joined and put the effort on the map. I worked with Andrew Layman, David Turner, John Montgomery, and others at Microsoft to bring IONA into the picture as a SOAP supporter and, in fact, as the first J2EE vendor to support SOAP. IONA demonstrated Web services interoperability at several Microsoft events during that year. The Microsoft presenter would introduce its SOAP Toolkit and demonstrate interoperability with a COM server. Then the IONA presenter was called on to describe how the same SOAP interface could interoperate with a Java server.

After that, I organized IONA's initial participation at W3C, supported the establishment of the XML Protocols Working Group, helped write the group charter, and began representing IONA at the XML Protocols Working Group, and more recently, at the Web Services Architecture Working Group. IONA has supported the submission of SOAP to W3C, WSDL, SOAP with Attachments, and XKMS. One thing led to another, and I eventually took on the responsibility of delivering IONA's implementation of Web services integration technologies.

In October 2000, I represented IONA at the UDDI kick-off meeting. It was then that I realized the potential for Web services technologies for application integration inside the firewall. Why not use SOAP, UDDI, and WSDL for internal projects? Then you could use the same approach for integration, regardless of whether it's inside the company or across the Internet.

David Vaskevitch presented at the UDDI conference, and this reminded me of the 1995 chapter in The Future of Software that I coauthored for Digital Equipment Corporation. David was author of the Microsoft chapter in that same book. In the Digital chapter, "The Key to the Highway," Peter Conklin and I compared the potential power of software standards to the impact of standards on the automobile. Standardized parts enabled mass production, which revolutionized the industry and society. Today, software remains essentially a craft business, as automobiles were at the start of the twentieth century. Having widely adopted standards has remained elusive despite many attempts. We may be at the crossroads; Web services may finally do the trick.

I hope this book helps you understand what Web services are all about. If it serves as a decent introduction to the main ideas, concepts, and technologies, it will have done its job and find its place in the Web services community.

Up-to-date, complete and accurate, May 22, 2002
This is a no hype book that thoroughly covers all you need to know to develop non-proprietary, standards based web services. There is no gushing fluff about how great web services are and why it's the best thing since sliced bread. Instead you get a complete, factual overview of what web services are and are not, and the building blocks available to design, develop and implement them.

All of the important pieces are covered (XML, WSDL, SOAP, and UDDI), as are the standards. Alternative pieces, such as ebXML, are also given objective treatment.

If all you want to do is learn about web services without getting bogged down in an author's technical politics, get this book. It's a refreshing change from the ones that have flooded the market in recent months.

Highly recommended, September 8, 2002
In my role as a solutions architect, I find myself having to read vast quantities of technical material, much of which is sadly lacking in substance, diluted to the point of uselessness, biased in a particular technology (or vendor) direction, or simply just poorly written. Eric Newcomer's book is a refreshing change from much of the material I have had the misfortune to read lately - it is a well-written work that provides the reader with an excellent overview of Web Services and the use of the associated technologies. The book provides a well-balanced discussion of the various key technology areas (XML, WSDL, SOAP, UDDI), and includes many useful insights into the issues associated with these technologies and where the technologies are heading, based on current industry usage and standards formulation. The history of each technology area is discussed, providing the reader with useful background information. Attention is paid to the salient points, rather than getting bogged down in unnecessary details that might be readily obtained elsewhere. To this end, it is worth noting that a most pleasing feature of this book is the inclusion of a comprehensive bibliography, allowing the reader to readily identify sources of more detailed information on particular subject areas, if required (many of the references are freely available via the Internet).

As clearly stated in the introduction, the book is intended for IT professionals who need to understand Web Services, how they work, and (most importantly) what they are good for - the book is not intended to describe how to implement Web Services using a particular product offering from IONA (Eric Newcomer is the IONS CTO) or any other vendor. It is clear that Web Services are going to have a huge impact on the way we look at distributed computing, however it is also clear that the whole area of Web Services is still evolving. The book does not present Web Services as a 'silver bullet', but instead gives the reader a balanced perspective of the topic, thus providing a sound basis for informed decision making. Much of the material is presented in such a way that it can be readily understood and appreciated by less-technical IT professionals (such as managers like mine that no longer perform a technical role within the organization but want to understand what the heck I'm talking about).

With regard to implementation architectures such as Microsoft.Net and J2EE, the book does not pitch one technology against another, but instead simply states the facts, allowing the reader to formulate their own (now informed) views on these and other such tools and technologies, where and how they might be used, and so on. In addition to covering the main technology areas (XML, WSDL, SOAP, UDDI) the book also discusses alternative approaches to Web Services (ebXML) and perhaps less well-known technologies such as XML-RPC and Reliable HTTP, and what role these technologies might play in future developments. It is interesting to note that the SOAP specification is still being heavily debated, while XML-RPC has been stable for close to five years with implementations existing in many different programming languages. It is possible that some of these alternative technologies will play an important role in the future of Web Services, and a discussion of these technologies is most useful.

In summary, I found this book to be easy to read and highly informative. The writing style is clear and concise, and the book delivers pretty much exactly what it claims to. Wide and informed coverage is given to the subject area, and a comprehensive bibliography serves to provide a means of tracking down further information. The role of Web Services is clearly defined and a balanced discussion as to where and how they might be used is provided. Future developments in the Web Services space are considered, and the inclusion of material on less well-known technologies combines to make this book one of the most complete works on the subject to date. I would highly recommend this book to any IT or software professional interested in or needing to understand Web Services.

Good Introductory Book to Web Services, July 4, 2002
Getting a grasp of Web Services is immensely difficult. Every vendor has a different version - often twisting it to suite their commercial needs.

I have been working with the fundamentals for Web Services for over two years, and I have been amazed at the hype to which it has succumbed. Some of this hype is justified and it can be daunting separating facts from fiction.

I was pleased Eric Newcomer's book - it provided a relief from hype and grounds for clear thought. Mr. Newcomer approached this book from the ground-up and does not patronize the reader with unsubstantiated claims.

This book is recommended to the reader that is curious on Web Services and would like a book that can provide a launching pad towards understanding the subject.

In this book you will find:

- How Web Services evolved
- The technology that makes it happen
- The promises of Web Services
- Different software vendor's strategy on Web Services

You will not find how to get started on running your first Web Services projects - that information can be found online or in another book.

In this book you can expect to find the foundation that will give you a good perspective on Web Services. Upon reading this book, you will be able to discern which areas of Web Services that will interest you the most. Armed with this knowledge you will be able to read materials on Web Services, immune to being swayed by marketing hype.

Best wished on your Web Services journey - it is an exciting field.

I hope you find this review helpful - please let me know if you have any questions or suggestions.

One of the Best, June 23, 2002
This is one of the best books I've found to date on web services. It sits half way between what I call the protocol books (you know: the O'Reilly sea-creature series) and strategy books such as the one I'm currently writing. What impressed me most was the book's thoroughness. Although it's clearly aimed at developers and includes a fair number of XML examples, the book contains few code listings. (When you're ready for that, you need the sea-creature books.) Instead, Understanding Web Services gives equal time to technology, standards, strategies and Eric's own perspectives on the offerings of the major vendors. (Eric is the CTO of IONA.) If you want to know what web services are all about, with an emphasis on the technologies, this is the place to start. I only wish this book had been available when I was ramping up.

Good overview of the technologies, but really technical, January 5, 2003
Eric Newcomer's "Understanding Web Services" provides for a solid theoretical overview into the world of the new web technologies, including XML, WSDL, SOAP and UDDI. For a newcomer into the field, this book is a good start to understanding to what these technologies are and what they can do for business.

THE CONTENTS:

Here are the topics that Newcomer addresses:

1. Introduction to Web Services (XML, WSDL, SOAP and UDDI)

2. XML - Describing Information

3. WSDL - Describing Web Services

4. SOAP - Accessing Web Services

5. UDDI - Registering Web Services

6. ebXML

7. Other Web Service technologies

8. How to Implement

THE ANALYSIS:

Overall, this book is a great teaching and learning tool to the basics of web services. Newcomer does a fine job of describing the various technologies and trying to "dumb" down the technology to describe how it works. One of the great things about the book is the "margin" notes on each page that highlight the definitions and key concepts that he tries to highlight. This makes the book easy to follow along with and helps to reinforce the concepts. Overall, this is great for a textbook.

However, keep in mind that the subject is very technical so if you are not a techie there are parts where you WILL get lost. Overall though, you still come away with a good understanding of what these technologies are and how they can help your business.

THE VERDICT:

Overall, Newcomer does a fine job of covering the various technologies and issues that deal with web services and how they can be applied to business. While the subject is technical and you may got buried in some parts the book's style is still easy to follow. This book was used as a text for an e-commerce web services course I took during the Fall of 2002. Whether you are studying this subject independently or whether you are an instructor looking to use this book for your course, Newcomer's "Understanding Web Services" is a good choice.

Highly Recommended

Great book for architects and technically inclined managers, September 4, 2002
Eric Newcomer's book was written for the well read architect, technically minded manager, or developer who is interested in more than just bits and bytes. If you are interested in 'how to implement a Web Service in language X or Y', then look else where. If you have the mind for the bigger picture then this is the book for you. Although Eric Newcomer is CTO of IONA this book does not suffer from the typical vendor marketing hype that one has to typically wade through, more importantly being involved in the major organisations defining the Web Service standards he is able to give you an up to date well balanced opinion of where each technology (SOAP, WSDL, UDDI etc) is heading and problems facing each one.

For an architect or manager who has the responsibility of planning the future EAI strategic direction for the company this book provides an honest basis to make well informed decisions e.g. does one move towards ebXML now or wait, or choose SOAP, WSDL, UDDI as they appear to be heading. The book is easily read, starting with the basics, moving on to the core technologies making up Web Services, then to the less well known technologies being floated, finally to an overview of the product offerings from the major vendors. No book can be all things to all people and where Eric Newcomer has thought appropriate he has referred the reader to further reading.

In summary I can highly recommend this book to those who want to know:

- what are Web Services,
- where do they fit in to my organisation,
- where are Web Services heading and the problems they face,
- who/what are the main driving forces behind Web Services,
- how do the technologies (SOAP, WSDL, UDDI etc) fit together,
- what other technologies are currently being floated.

Web Services are posing an exciting future as a mechanism for `globalising' the world of bits and bytes, this is a great book to come to grips with the world of Web Services.

Good for Introduction at Leisure!, January 25, 2003
Well, I bought this book thinking that it would get me started with developing web services, apart from just introducing them.

Though it does a pretty good job of introducing them, its the getting-you-started-with-development part that it fails to impress. Probably it just isn't designed to do that.

So if you want to read an introductory text on web-services at leisure, this book is a good choice. Its written in a very comprehensible style and I had no problems understanding the key concepts.

However, as is true with any other XML based technology, unless you get some hands on experience with the whole framework, you don't really feel that you are ready to begin professional work as yet. And since XML-based frameworks are usually very detailed and intimidating at first, real-time experience becomes all the more important. I guess now I need to buy another book that'll help me with actual development of web-services .

This book does not give insights on the topic, August 10, 2002
This book apparently is intended for high-level managers and end-users of the technology, since it gives no technical details on how these technologies are used. That would be okay, except that at the managerial or end-user level I find the book to lack insight into what the technologies do or how they do them, at any level. Rather, it is mostly gives lists of "things that happen", with no logical connection from one thing to another, with no insight as to why this makes sense. It is like memorizing dry facts in a bad high school history class: yes, I could memorize them, but why, and who cares anyway?

Good defintions of every term...that's all, July 16, 2002
I did not find this book very helpful to implement web services.
I would say it's the introduction of webservices like a first lecture of a semester long class. You got the idea.

Good coverage, difficult read, April 9, 2004
I have been thrown into the web services technology without a parachute and this book has helped to put things into perspective. You are not going to sit down and write code from this book, but it does help to define all of the pieces of web services technology and get you started.

With that said, this was a difficult book to read because the writing style is very abrupt, does not flow, and reads like an old style academic textbook trying to impress and confuse the student. I've read more technical books that were easier to understand because they explain their subjects in more natural prose. I found myself frequently reading pages over one or more times.