A biologist explains her own and others' research into the ebb and flow of human sexuality and offers some thoughts about the implications of their findings. Cutler (Hysterectomy Before and After, 1988, etc.) asserts that the moon's influence is dominant in human sexual cycles and that recognizing the power of the cosmic forces on our bodies' biorhythms is essential to our well-being. A favorite image of hers is a swimmer in a panicky struggle against rough ocean waters versus a floater who lets the rhythm of the waves carry him safely to shore. According to Cutler, Ecclesiastes had it right: There is a time to love and a time to refrain from loving. More specifically, research indicates that regular weekly sex is beneficial to women's health; when that's not possible, celibacy is the best alternative, for sporadic sex can have serious health consequences; further, abstinence during the menstrual period can aid women in avoiding health problems. Her work on pheromones makes fascinating reading and could have been a book in itself. Cutler tries hard to hold the interest of the general reader with catchy section heads and chapter titles (witness the book's title), but at heart she is a research scientist who laces the text with tables and charts that require close attention. For the nonscientist, who may need a little help, she sums up her conclusions rather neatly at the end of each chapter. For her fellow scientists, she provides copious notes keyed to individual sections and references for each chapter. Cutler, who never lets the reader forget that she herself is a woman, seems interested primarily in female sexuality, and her appeal is likely to be to women. A strange mixture of science and speculation that reveals an inquiring mind at work.