In 1975, when the young Czech tennis star defected to be able to play where and when she wanted, she had hopes--underlined here--of becoming Number One; after all, she was beating the unconquerable Chris Evert. But now that the charm of her high spirits and heavy spending has worn thin, and her performance has fallen off, she doesn't hold up as a heroine for all the authors' efforts. ""The girl to watch"" had, it seems, remarkably few obstacles to overcome. She came from a tennis-playing family, her natural talent was carefully nurtured, she moved readily from national titles to world tournaments to the US professional circuit. Her chief problem was a bad temper--and, as related here, the Czech Tennis Federation's unease at her all-American behavior. Whether or not her playing would have been curtailed, there's no knowing. Independent, she apparently is; sympathetic or admirable, not really.