The fourth edition of this best-selling field guide has been completely revised and updated to include the latest information from leading astronomical sources. All the time-sensitive material is new and valid through 2017: solar eclipses, phases of the moon, positions of the planets, and more. Twenty-four Monthly Sky Maps, all newly revised and in color, show exactly what you'll see when facing north or south in the night sky. Fifty-two Atlas Charts, also revised and in color, cover the entire sky, including close-ups of areas of special interest such as the Pleiades and the Orion Nebula. The hundreds of thousands of devoted users of the previous editions of this guide have been eagerly awaiting this new volume so they can continue to enjoy their hobby in the coming decades.