This is a classic, well worth (re-)reading twenty years later. The author's later EXPLORING THE WORLD OF LUCID DREAMING isn't actually more _comprehensive_ than this book, but rather more practical, "a step-by-step guide to lucid dreaming: how to do it, and what to do with it." LUCID DREAMING, in contrast, includes material on NDEs, OBEs, dream telepathy, mutual dreaming, and other topics for which lucid dreaming has important implications. It is a _different_ book, addressing "why?" sorts of questions, perhaps with more philosophical depth, and certainly more implications, while EXPLORING... focusses on "how?"'LD techniques, and "what?"'LD applications.
LUCID DREAMING is currently out-of-print, but widely available in libraries, used book stores, and conveniently'Amazon.com. If you are interested in dreaming and transcendence you'll want to read this book. And if you're interested in lucid dreaming, you'll want to re-read it.
A good book but try "Exploring the World of Lucid Dreaming" from the same author. Much more comprehensive written after this book.