Volume 9 in this series consists of four chapters on vectors that affect human or animal health and six chapters on plant pathogens and their vectors. In Chapter 1, Alex S. Raikhel discusses vitellogenesis in mosquitoes: the cornerstone of the reproductive cycle involving massive production of yolk precursors by the fat body and their accumulation in developing oocytes. In anautogeneous mosquitoes, vitellogenesis is dependent on the availability of a blood meal and, as a consequence, is linked to transmission of pathogens. Therefore, elucidation of mechanisms governing the mosquito vitellogenesis is critical for the successful development of novel strategies in vector and disease management. Previous reviews on mosquito vitellogenesis have dealt predominantly with hormonal control. The goal of this review, however, is to summarize significant progress which has been achieved in understanding mosquito vitellogenesis at the cellular, biochemical and molecular levels. It is with these disciplines that we expect to fully understand the mechanisms governing this key process in mosquito reproduction.