The first edition of this very successful book was one winner of the Astronomical Society of the Pacific 'Astronomy Book of the Year' awards in 1986. There are a further seven subroutines in the new edition which can be linked in any combination with the existing twenty-six. Written in a portable version of BASIC, it enables the amateur astronomer to make calculations using a personal computer. The routines are not specific to any make of machine and are user friendly in that they require only a broad understanding of any particular problem. Since the programs themselves take care of details, they can be used for example to calculate the time of rising of any of the planets in any part of the world at any time in the future or past, or they may be used to find the circumstances of the next solar eclipse visible from a particular place. In fact, almost every problem likely to be encountered by the amateur astronomer can be solved by a suitable combination of the routines given in the book.