This book gives me all I need to Know
Granted, I have written lex and yacc apps in the past, but, I learned how from simply reading the Unix documentation..this is far superior. It also teaches a little about grammars and gives great sound examples. You must be willing to wade into cold water without flinching, however, and this is not for the "sunday morning programmer". The concepts are higher level computer science concepts, not high school hacker. Great book, great tool!