DCOM is just another disposable technology. As such, it was a complete failure; one that the marketing folks at M$ have tried to bury as quickly as possible under an avalanche of .NET hype.
DCOM was hard to port because, like COM, it is based on a binary standard (i.e. a standard that changes when you leave x86 and go to 64-bit RISC). Not only that, but DCOM doesn't support distributed transactions. Worst of all, DCOM is a very, very complicated technology to use. Three strikes... YOU'RE OUT!
The half-wit MBAs at Micro$oft realized their mistake and have abandoned DCOM, leaving it forever in the backwaters where the only record of its sorry existence are stupid books like this.
I have no idea why someone would want to buy this book. Folks, this is a dead technology. It is no more. It is an ex-techology. If you buy this book, you are lying to yourself. This book will sit an gather dust, unless you can find more productive uses for it...like burning it to stay warm.