Contents. List of Contributors. Preface (E.E. Bittar). To Divide or Not to Divide? That is the Question (H. MacKinnon and D.A. Gilbert). The Cellular Biology of Mammalian Fertilization (P.M. Wassarman). Cell-Type Determination During Development (P.W. sternberg and J.E. Mendel). Unstable Cytodifferentiation (D.J. Pritchard). Cell Adhesion and Recognition in Development (G.B. Grunwald). The Role of Gap Junctions During Development and Patterning (C.R. Green). Ontogeny of Hormone Receptors (G. Csaba). Cell Regeneration (M.G. Ord and L.A. Stocken). Cells and Senescence (R. Rosen). Author Index. Subject Index.