Hi, I want to buy a book about crowd behaviour. It would be a plus if it is written with games in mind.

Any recommendations?

That's... pretty open-ended.

Are you talking about psychology i.e. how real crowds behave? Or simulating that psychology? Or both?

What is your actual goal? Some books may be suitable for that purpose and some may not.

I am talking about both.

My goal is to create a game where the player controls a swarm of birds. So I need to educate myself on this topic. I know there are some tutorial / articles on the internet but I prefer to read these things from books, as they tend to explain things better and in more depth.

So yes, I would like to learn about the psychology and also simulating that psychology.

EDIT: I don't mind getting one book about the psychology and another book about it simulation.

If all you need is a swarm of birds, the canonical articles on flocking and steering behaviors should be plenty to get you started. It's pretty simple stuff and doesn't really merit a whole book, generally speaking.

Movement behaviour is a common topic on any AI for games book, you can check this oune out: http://books.google.com.mx/books/about/Artificial_intelligence_for_games.html?id=1OJ8EhvuPXAC&redir_esc=y