Together with other volumes in this series, Volume 56 of Current Topics in Developmental Biology presents thoughtful and forward-looking articles on developmental biology and developmental medicine. Reviews include: Selfishness in moderation: evolutionary success of the yeast plasmid Nongenomic actions of androgen in sertoli cells Regulation of chromatin structure and gene activity by Poly(ADP-ribose) polymerases Centromeres and Kinetochores, Who Needs 'Em? The Role of Non-centromeric Chromatin in Spindle Assembly Modeling Cardiogenesis: The Challenges and Promises of 3D Reconstruction Plasmid and Chromosome Traffic Control: How ParA and ParB Drive Partition The exceptional reviews in this volume of Current Topics in Developmental Biology will be valuable to both clinical and fundamental researchers, as well as students and other professionals who want an introduction to current topics in cellular and molecular approaches to developmental biology and clinical problems of aberrant development.