Of all the introductory astronomy books out there, this is by far my favorite. Dickinson's descriptions are always models of scientific accuracy and clarity, and his book is richly illustrated with diagrams and photographs, many of which he has taken himself. I can think of no better way to get acquainted with amateur astronomy than by reading this book.
Although it covers much the same ground as NightWatch, this book, now in its third edition, goes into much greater detail. I particularly value its detailed examination of currently available astronomy hardware, with very specific recommendations on what to buy and what not to buy, and its up-to-date section on astrophotography.
Beginners will find its detailed instructions on setting up and using a new telescope particularly valuable.
Written primarily for owners of small refractors, this is a wonderful introduction to finding and observing a variety of astronomical objects. It assumes absolutely no knowledge of how to find things in the sky.
This is the best single volume guide to finding astronomical objects. Using a series of "Sky Windows" it provides detailed starhopping information for all the Messier objects plus a whole additional bunch of objects.
It also is exceptional for telling you what to expect with each object and filling you in on what you are seeing, making it a rich experience for observers at all levels.
Sue French has built a devoted following from her monthly columns in Sky & Telescope magazine in which she tours a particular region of the sky. This book collects a whole series of her guided tours in one handy volume.
Maybe you're getting ready to take the plunge into astrophotography. If so, this is the best single guide to the whole field, covering techniques and equipment in detail.
Nowadays, film astrophotography has become a relic of the past, and all serious astrophotography is done digitally with digital single lens reflexes and dedicated CCD cameras.
This book by one of the pioneers in the field is full of detailed practical help using the latest available equipment.
Geoff has been a life-long telescope addict, and is active in many areas of visual observation; he is a moderator of the Yahoo "Talking Telescopes" group.