The Howdunit Forensics book covers everything from DNA testing, to forgery, to asphyxia, and it covers it thoroughly.
For testing methods (i.e. paternity, DNA, etc.), the book will give you procedures, uses, how long they take, what kind of materials can be used to carry out the tests, the shortcomings of each test, and more.
For murder situations such as asphyxia and gunshot wounds, "Forensics" covers different types of strangulation and goes into how investigators can tell them apart. It's very specific, very informative, but not so informative that the reference feels like a textbook. There were times when I looked up a couple of things on the internet to supplement the information in the book, but it's a reference book, and in that regard, it does its job extremely well. And it definitely makes research a lot easier.
I really don't have anything to complain about with the book. Great for writers, easy to read/understand, just an all around good reference book.