Nijinsky, the dancer who seemed to rest in mid-leap; Bronislava Nijinska: Early Memoirs, translated and edited by Irina Nijinska and Jean Rawlinson, with an introduction by Anna Kisselgoff. New York: Holt, Rinehart & Winston. 546 pp. $22.50.

Although it has been more than 60 years since Vaslav Nijinsky danced for an audience and more than 30 years since his passing, the legend of le dieu de la danse lives on.

Those who saw him perform on the stage of the Imperial Theater in St. Petersburg during his years with the Diaghilev Ballets Russes (1909-13), or on the American tour (1916-17), never forgot the image of Nijinsky soaring in the air and ''resting for a minute,'' as he once commented, before returning to earth.

Legends hover around the roles he created: the Specter of the Rose, the Faun, Petrushka, and others, even though contemporary audiences never saw Nijinsky dance. And there was lots of talk about the mental problems that increasingly beset him.

Feeding the myths about the greatest male dancer of his era was a long series of articles and books: the biography published by his wife, Romola, in 1933, her publication of Nijinsky's diary in 1937, the appearance of a book by fellow dancer Anatole Bourman in 1937, and books written in the 1970s by Richard Buckle , Lincoln Kirstein, and Soviet ballet historian Vera Krassovskaya, respectively.

But this new collection of the memoirs of Nijinsky's late sister, Bronislava, gives us a fuller picture of Nijinsky's childhood and creative years than any of the others

As the beloved and trusted younger sibling, Nijinska followed her brother through life - in childhood games; at the Imperial Theatrical School, where both were students for ballet training and academic subjects; onto the stage of the Imperial Theater; and into the Diaghilev company. Later, when Nijinska became a choreographer in her own right, she felt she continued the experiments begun by her brother.

Nijinska was not with her brother when he married Romola de Pulszky on the South American tour of the Ballets Russes. She was in Russia, waiting for the birth of her daughter, Irina, the co-editor of these memoirs. One wonders if the controversial marriage would have taken place after the 10-day shipboard romance if Bronislava had been there.

Nijinska's memoirs provide a wealth of details about the family. The dashing but volatile father, Thomas Nijinsky, and the gentle mother, Eleonora Bereda, were at one time students at the ballet school of the Warsaw Wielki Theater, then performers in Poland and Russia. Vaslav, Bronislava, and their older brother, Stanislav, traveled and occasionally danced with their parents. Vaslav, like his father, showed special gifts for high jumps.

Nijinska's portrait of the mischievous young Vaslav shows us a child overwhelmingly curious and willing to take risks. In contrast to other reports, Bronislava's memoirs attribute her brother's low grades in school to impatience rather than dullness. Vaslav also showed a musical inclination during childhood, playing the balalaika and the piano, even though he could not read music. He could memorize entire opera arias as well.

While still in school, Nijinsky was given dance roles with the imperial company, no doubt one of the reasons for his segregation from the other students. This was eventually blamed for damaging him emotionally. Except for Bronislava, he was close to few of his dance colleagues; later he had difficulty working with them as a choreographer.

Nijinska is understandably reticent about her brother's homosexual relationships with Prince Lvov and Sergei Diaghilev, calling them ''close friendships.'' Rounding out the earlier accounts describing the young Nijinsky as a ''blank'' in the lively discussions among Diaghilev's circle, Nijinska says that at home her brother repeated everything that was said by the great artists; she attributes his reticence to shyness.

Nijinska describes the ballet training she and her brother received and how he worked to perfect his technique. Most revealing are her discussions with Diaghilev, who had evidently decided to fire Nijinsky, even before the South American tour and his marriage, because Diaghilev needed to rehire Michel Fokine as company choreographer.

In all, this is a book ballet buffs will treasure, as they await the publication of Nijinska's later memoirs.