This is the best programming book I've ever read. Each chapter is well-structured and concentrates on language specifics, sparing the reader from revising concepts like object-orientation over and over again. But the best part is, it actually made me laugh.
Rather than being an expanded version of online documentation, this book takes a top-down approach to efficiently cover the bare essentials and get stuck in. Later chapters look at specific parts, such as regular expressions, in more detail.
While there is some repetition between chapters, I find this helps me to learn. However, the book does aim to be comprehensive, so expect some more esoteric content later on, including character encodings a large chunk of the language reference.
Improvements: Remove the language reference in favour of online chapters.