The haploid-diploid alternation of generation is among the most fundamental features of eukaryotic life. Until recently, however, little research had been done on the origin and evolution of this genetic system. Bringing together for the first time emerging empirical and theoretical perspectives on this topic, this volume contains the proceedings of the 1993 Symposium on Some Mathematical Questions in Biology: The Evolution of Haploid-Diploid Life Cycles, held in June 1993 in Snowbird, Utah. The volume opens with a broad survey of life forms which reveals a wide diversity of life cycles, including predominantly haploid cycles, predominantly diploid cycles, and mixed cycles. Mathematical models attempt to explain this diversity in terms of evolutionary forces that include deleterious mutation, advantageous mutation, and ecological selection. A review of the first experimental studies shows how the hypotheses suggested by the models may ultimately be resolved. The book introduces biologists to mathematical approaches to these problems and introduces mathematical biologists to comparative and experimental approaches. Opportunities for future research are highlighted throughout.