Microsoft's technology for distributed computing revolves around DCOM and given a current industry trend towards components and business objects this is clearly an important technology. The focus of this book is to explain DCOM to developers, primarily those using Microsoft's tools; in particular Visual Studio and BackOffice, as all of the examples are geared towards them. The example code is available via FTP from Wrox.
The layout and presentation is good, the code samples are short and relevant and you make progress quite quickly. Along the way you cover all of the major topics such as monikors and binding, streaming, marshalling, directories and transactions. There are also other odds and ends such as clustering which is also explained clearly.
The author has a very conversational style, which may not be to everyone's liking but he is able and does, break down what is a complex subject into manageable chunks. Those chunks are very often illustrated with a segment of (normally C++) code or a step through of a wizard (Visual C++) process. This step-wise approach allows the reader to build up their knowledge until by the end of the book they have a much bettergrasp of the subject.
For non-developers, such as (project-)managers, this book is probably at a level of detail that obscures the purpose and architecture and consequently has less value. For developers that use non-Microsoft tools or do not have access to all of the tools used in the examples (Visual Studio and BackOffice) then again the focus is probably too restrictive. However, for developers using Microsoft tools wishing to get to grips with DCOM and understand the next probable architecture after Client/Server this is a useful book, although a tad expensive for ~450 pages.