The man in the Moon and his frogs, rabbits, sheep and dragons

The surface of the Moon is indeed rich in detail. Quite apart from the large dark areas so easily visible with the naked eye, and once believed to be seas, there are mountains, hills, valleys, ridges and features of all kinds, though the scene is dominated by the walled formations always known as craters.

It might be thought that naming these features would be a straightforward process. In fact it has proved to be nothing of the kind, as Ewen Whitaker shows in this absorbing new book.

Pre-telescopic sketches were of course rudimentary. Apart from the famed man in the Moon, there were representations of frogs, rabbits, sheep, and even dragons.

The situation changed in the early 17th century with the invention of the telescope.

The first telescopic lunar map was English, due to Thomas Harriot; it pre dated Galileo's chart of 1610, though it remained largely unknown until by good fortune I tracked it down in 1965 and arranged for its publication. Like Galileo's chart, it showed various features in recognisable form.

Names were soon introduced, for example by the French astronomer Pierre Gassendi, whose system has not survived (his "Caspian Sea" is known today as the Mare Crisium). Other systems were equally short-lived.

A new system was introduced in 1651 by the Jesuit astronomer Riccioli, and it is this which has - to all intents and purposes - survived. Riccioli produced a new map, showing the "seas"; for craters he used the names of famous persons, usually scientists.

The system was not without its blemishes, but all in all it proved to be satisfactory, and has stood the test of time even though it has been drastically modified and extended. Improved telescopes led to improved lunar maps, and many new names were introduced.

There was a period, extending from the 19th century well into the 20th, when various selenographers introduced quite arbitrary systems of their own, leading to a great deal of confusion and even unscientifically acrimonious controversy.

However, the situation was eventually stabilised by the International Astronomical Union, the controlling body of world astronomy, which also assumed responsibility for naming features on the Moon's far side, never visible from Earth.

Whitaker has been in the forefront of lunar cartography for many years and is probably the world's leading authority on the subject of nomenclature. He is therefore uniquely qualified to write this book, and he has carried out his task well.

The book is very detailed, with excellent reproductions of the various maps; the text has clearly taken many years of careful, painstaking research, and contains much information not to be found elsewhere.

Whitaker and his publishers, Cambridge University Press, are to be congratulated for a book that, in this particular branch of scientific history, is certain to remain the standard.

Patrick Moore is the author of more than 60 books, mainly on astronomy.