Those who love to watch great dancers in action have the luxury of believing that the secret is self-expression. In reality, the secret is technique, and, in whatever form of dance, it takes a lot of training even to be mediocre. Nor does the technique of one form of dance automatically transfer to another. Tamara Karsavina, who first danced the title role in the ballet Firebird, was an admirer of the American free-form dancer Isadora Duncan. But Karsavina, in her marvellous book Theatre Street, pointed out a cruel truth: though ballerinas might have copied what Duncan did, she herself was never able to copy them. In this section I have set out to mix examples indiscriminately from ballet, jazz dancing, tango and more, but only on the understanding that they are separate disciplines. My excuse for treating them as all the one thing is that the best practitioners in each field have always had the same effect on my emotions. In the top layer of achievement in any form of dance, the same extraordinary thing seems to be going on: the movement of the human body to music becomes as expressive, and as inevitable, as poetry. The result is pure joy for the spectator, but it always starts from hard work by the artist. When asked the secret of his ability to gain altitude on stage, Nijinsky said, “I merely leap, and pause”. But he was kidding. Gene Kelly spoke the truth: “If it looks like you’re working, you ain’t working hard enough.”