The best book I've found on basic structure. Also, it has three excellent interviews at the end which are inspiring and helpful to read over and over again.

A great book for directors and playwrights, and I feel that a great playwright must know about directing. This teaches you how to read and analyze a play not to write a paper on it, but to put it up on stage where it belongs.

Erik Ehn (a fabolous and poetic playwright) uses this when he teaches. I have not read it, but it's about unlocking creativity.

And now, some plays. This is my favorite play, a dark, dark comedy of social satire.

duh.

Another collection that dares you not to change how you write.

A great play with amazing scenes. Taught me that a play is a summation of it's scene, so everyone has to be interesting and amazing on their own.

Best translation I've read of four essential plays.

Brilliant reading of Chekhov. This book looks at his dramatic technique, a warping of Greek drama theory. Will change the way you write.