In sexually reproducing organisms, germ cells give rise to gametes and serve as the link between generations. A key event during germ cell development is the decision to leave mitosis and enter meiosis, leading to the formation of mature eggs and sperm. Germ cell development involves unique gene expression programs and the establishment of epigenetic marks that ensure success during fertilization and embryo development. Written and edited by experts in the field, this collection from Cold Spring Harbor Perspectives in Biology reviews the biology of germ cells in metazoans. The contributors...