This is the first detailed treatment of the long-standing, previously unresolved controversy surrounding the nature of senescence in clonal cultures. Part historical review of the literature, part detective story, Sex and Death in Protozoa presents a comprehensive but entertaining discussion of the sometimes contradictory evidence for protozoan senescence and the rejuvenating effects of sex in these organisms. Drawing on Hermann Muller's "ratchet model," Dr. Bell demonstrates in a quantitative fashion how genetic recombination (an intrinsic part of the sexual process) can eliminate the deleterious effects of accumulated mutations in clonal cultures and provide the rejuvenating effects associated with mating. This well written account by one of the