Political book

I'm looking for a book that explains different political theories. Like democracy, communism, socialism, anarchism, etc. Maybe subtypes of them as well. A political science type book I guess it'd be. And I'd prefer it to be more readable than just a textbook.

Any suggestions?

Sociology text book, google it

The Worldly Philosophers by Heilbroner

while the focus is economics, it covers Adam Smith, Marx, some early Anarchists. very readable and informative.

I just recently read a good book about the history/developement of democracy, and I know that Noam Chomksy takes a good shot at anarchy. Uhm, there's also the anarchy faq all over the net, although you must realize that the one you're looking for is not (death destruction chaos).
and, of course, depending on who you talk to, the communist manifesto is good for a socialist ideal.
uhm, that's all i can pull outta my ass.