From the preface:
Who should read this book?
Because this book can be used in several different ways, it has several distinct possible audiences. Part 1 is an introduction to rule based systems for any student of information technology, practitioners and management alike. The later parts of the book are aimed squarely at programmers. I've assumed an intermediate knowledge of the Java programming language throughout. Occasionally I'll explain a Java concept, but most of the time, I'll just imagine that you understand.
The audience that I thought of most as I wrote were intermediate Java programmers with little or no exposure to rule based systems, who are interested in getting that exposure.
This book is also suitable as a text for a university course on practical rule-based systems development. The course prerequisites should include a course on Java programming. The course content would include Parts 1, 2, and 3 of the book, followed by either Part 5 or Part 6. Additional material could be used as time permits, of course.
I also dug up my old reply from
here:
I like to think that J.I.A. can stand alone; it really doesn't assume you have any background in rule-based systems. I also happen to know that if you start reading it and have any questions, you won't have any trouble finding answers to them at JavaRanch... 
If you do find, though, that you need to get some background first, there are really a dearth of other practical books about rule-based programming. Peter Jackson's book is usually considered the canonical reference, but it's pretty dry and academic. Giarratano and Riley's massive (and expensive) tome spends more than half of its length explaining unrelated things like the waterfall model of software development; in the second half it does spend a few chapters doing a basic tutorial in the CLIPS rule language but the examples are trivial and not realistic.
