Because this book has been designed to interest you in the observation of variable stars, it is not filled with graphs and formulae or explanations of variation. There are other books that tell you that, as well as other branches and ideas of astronomy, and here are some of them.

Bishop, Roy, ed. The Observers Handbook: annual. Toronto: The Royal Astronomical Society of Canada. One of the best of the annual guides to the night sky.

Calder, Nigel. Violent Universe. New York: Viking, 1969. This vibrant book injects a healthy dose of enthusiasm into what is known about the expanding Universe.

Campbell, Leon. Studies of Long Period Variables. Cambridge, Mass.: AAVSO. This 247 page volume, long out of print, is a landmark study of almost 400 long period variables based on decades of AAVSO observations.

Clark, David H., and Stephenson, F. Richard. The Historical Supernovae. Oxford, Pergamon Press, 1977. A useful discussion of ancient supernovae.

Dickinson, Terence. The Edmund Mag Six Star Atlas. Barrington: Edmund Scientific Company, 1982. A good atlas by a man who loves the stars.

Dickinson, Terence. NightWatch. Camden East, Ontario: Camden House, 1983. A superb introduction to ‘Viewing the Universe.’ Chapters on variables and other branches of observational astronomy.

Edberg, Stephen J., and Levy, David H. Observe Comets. Washington: Astronomical League, 1985.

Harwit, Martin. Cosmic Discovery. New York: Basic Books, 1981. Discussion of the process of discovery in astronomy.