This book is a work of art. Note, reader, this is not a beginner's guide to JS! The difficulty grows VERY quickly after the first few chapters. I must admit that the author strains a lot (sometimes unnecessarily) when it comes to giving examples. The exercises are difficult and really make you delve into the language. This is a book for JS enthusiasts looking to hone and develop an IT mentality. This book emphasizes and rewards clean and concise solutions. A great addition to your arsenal. One star minus because of the unnecessary bending that occurs in almost every chapter!