It is often called the "green dragon book"[1] and its cover depicts a knight and a dragon in battle; the dragon is green, and labeled "Complexity of Compiler Design", while the knight wields a lance and a shield labeled "LALR parser generator" and "Syntax Directed Translation" respectively, and rides a horse labeled "Data Flow Analysis". The book may be called the "green dragon book" to distinguish it from its successor, Aho, Sethi & Ullman's Compilers: Principles, Techniques, and Tools, which is the "red dragon book".[1] The second edition of Compilers: Principles, Techniques, and Tools added a fourth author, Monica S. Lam, and the dragon became purple; hence becoming the "purple dragon book". The book also contains the entire code for making a compiler.
The back cover offers the original inspiration of the cover design: The dragon is replaced by windmills, and the knight is Don Quixote.