Germ cells in sexually reproducing metazoa, through the germline lineage, are the route by which genetic material and cytoplasmic constituents are passed from one generation to the next in the continuum of life. Chapters in this book review germ cell development in the model organism Caenorhabditis elegans, discussing the biology, the genetics and the molecular mechanisms for various processes, as well as drawing comparisons with other organisms. Processes discussed include specification of germ cell fate, meiosis, gametogenesis, environmental/ physiological controls, epigenetics and translational control, fertilization and the oocyte-to-embryo transition. This book thus provides a comprehensive picture of the germline lineage and the continuum of life for the worm.