for beginner...any book that you recommend?

The only AI books I have are Mat Bucklands books. I like them, but I've never compared them to anything else. www.ai-junkie.com

I am going to have to say Mat Buckland's books are my favorite also. Most of the other books I read are only on theory or talk about it from a "You could do this... or you could do this..." without showing any code to back it up. "Programming Game AI by Example" shows you how to program the most basic and somewhat advance AI patterns to combine in later chapters for a small scale 2D FPS game with bots. Very useful and not that expensive. It has my vote.

While I agree that Mat's book is useful (heck, I have a copy sitting beside me and I use it as recommended reading for a 3rd yr behavioural robotics subject I teach), it is missing a lot of valuable and necessary information and only gives one limited perspective on many of the techniques that it presents.

I wouldn't recommend just one book, but rather I suggest you buy as many as you can afford so that you get to see the bigger picture. You can also find a lot of useful literature online. Other books I'd recommend:

-The Game AI Wisdom series and Game Programming Gems series
-Stuart Russell & Peter Norvig's excellent tome "Artificial Intelligence: A Modern Approach"
-Sutton & Barto's "Reinforcement Learning: An Introduction" (available online).
-Korb & Nicholson's "Bayesian Artificial Intelligence"

The above list increases in mathematical complexity, but introduces you to techniques that are very useful for designing everything from simple reactive steering behaviours through to deliberative, rational agents that can play games and learn about game play, strategy and even their opponents.

My best advice: start simple and build up through continual practice.

Cheers,

Timkin