The Routledge Companion series is a Godsend to students looking to get a solid overview of a particular field. I've enjoyed the Companion to Postmodernism and recommended to many friends. The RC Feminism and Postfeminism is a great addition to the series. Each area of feminism receives a nice essay detailing its thought and discourse while pointing readers to great primary and secondary sources. Since Amazon is nice enough to provide a table of contents, I won't duplicate that info here, but I urge you to check it out.

The historical and cultural essays are not so much thesis oriented as they are descriptive of the concepts and context. The authors don't critique the ideas, but they do present opposing views while explaining both sides. I found most to be extremely impartial.

Part II is a great cross-indexed dictionary of terms and names with short summaries, perfect for reminding yourself, say, who theorized on "ecriture feminine" or what Camille Paglia thinks of prostitution. The dictionary part is something I referred to frequently while getting familiar with feminist thought.

Naturally, this is an introduction and you'll eventually want to dig deeper, reading more specific writing. This is not the "only book on feminism you'll ever need", if indeed such a thing is even possible. It IS a great place to start with great recommendations for further reading. If you're new to feminism, check this out. Very highly recommended.