The IDA Pro Book, by Chris Eagle

Hex-Rays recommends The IDA Pro Book by Chris Eagle to give you the best insight into working with IDA Pro and the Hex-Rays Decompiler. In our view, this book is:

Comprehensive
It describes all major IDA Pro features in an easy to read format. Experienced users may be tempted to skip the first few chapters; resist this temptation and you will discover something new.
Accurate
It is very difficult to be detailed and precise when describing such a complex product. Chris does it extremely well.
Real
Handles real world malware, packers, and obfuscated code.
Profound
This is not just a collection of recipes or tricks but will give you a better understanding of the IDA Pro architecture, thus saving you from unnecessary frustration.