Glickstein introduces the reader to Emacs extensions and customizations. This book is an advanced tutorial for dedicated Emacs users. It is also a good introduction to aspects of Emacs that novice users have yet to think of or explore but from which they can probably benefit. The book begins with a description of its organization and ends with a list of Emacs Lisp syntax, which makes it a useful quick reference.

The book also introduces the Emacs flavor of LISP. Emacs Lisp is a full version of LISP that can be used to enhance editing on the fly or can be included in an Emacs initialization file or other files. This makes Emacs more than an editor: it is a programmable programming environment and a communications tool.

The reader is led, through a motivational series of common editing problems and editing mistakes, to create general solutions. Glickstein begins in chapter 1 by explaining how to customize key bindings. Chapter 2 explains how to create new editing commands. Although the book is short, the examples quickly become complex. Chapters 4 through 6 introduce searching using regular expressions, loading LISP files containing editing commands, and more features of LISP. Chapter 7 explains minor modes, which can modify or add to the features of major modes. Chapter 8 raises evaluation and error recovery issues. These are powerful features peculiar to LISP that make it possible to write code that is evaluated to code when you need it. Chapter 9 shows how to create a new major mode that can be made specific to file types in order to invoke the mode automatically. Chapter 10 introduces the final example, creating a crossword puzzle editor. This shows the power of Emacs to extend beyond the foreseeable uses of Emacs and beyond the uses of other editors.

Emacs users can produce a whole new environment, or even support asynchronous and interactive processes. In short, as others have said, Emacs is not just an editor--it is a way of life. All the example programs in the book are available in compressed form by anonymous ftp. While the editor wars rage on, Glickstein has produced a well-written, well-laid-out tutorial and reference.