This is a book for the amateur astronomer who wishes to carry out astronomical calculations using a personal computer with the minimum of fuss. It is not specific to any make of machine, neither are the programmes confined to specific calculations, Rather, it presents a collection of twenty-six subroutines, written in a portable version of BASIC, which can be mixed and matched according to personal requirements. Furthermore, the user need only have a broad understanding of the problem; the subroutines themselves take care of the details. For example, the routines can be used 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. Almost every problem likely to be encountered by the amateur astronomer can be solved by a suitable combination of the routines given here.