One of the most important persons in ballet history is Charles-Louis Didelot. Mary Grace Swift has written a most learned biography about him. In this scholarly volume, winner of the De la Torre Bueno Prize in 1973, there are many illustrations, both from Russian archives and from the British Museum and the Victoria and Albert Museum in London. Didelot (1767-1837) was born in Sweden and again I can note that I have a very famous compatriot in the field of dance. He was of French parentage and born in the reign of King Gustavus III who was known as "The Theatre King". But Didelot did not remain faithful to his king or the country of his birth. The king felt the need to write a rather desperate letter: "The contract of our Didelot is finished after the fire in the theater and I beg you to let him return as soon as possible, so that I again might have the pleasure of seeing him dance, as I cannot understand why we pay him when he is dancing in London". There is also a most interesting chronology of Dances and Pantomimes staged by Didelot. For the student of dance history this book provides the answers to many questions about early ballet. A most valuable document, painstakingly researched.