Though invaluable as a reference, however, Python in a Nutshell is discursive enough that chapters can be read comfortably, making it a great tool for learning new material. Individual sections provide a general introduction to the key classes and modules before going through their functions and methods. So I used the core language sections to learn what was new in Python 2.2. And, while its primary audience is obviously people already using Python, Python in a Nutshell could be used as an introduction to the language for experienced programmers.
Part one offers a brief overview and a guide to installation and invocation. Part two is an overview of the core language, covering the language basics, object-oriented methods, exceptions, the core built-ins, and the string and regular expression libraries. Part three covers the standard libraries and numeric processing and Tkinter extensions, ending with a chapter on testing, debugging and optimization, while part four covers network programming. And part five looks at extending and embedding Python, and at packaging Python software for distribution.
A full table of contents — and a sample chapter — are available on the O'Reilly web site.