This volume of Advances in Cell Aging and Gerontology critically reviews the rapidly advancing area of telomerase research with a focus at the molecular and cellular levels. The clearly established function of telomerase is to maintain chromosome ends during successive rounds of cell division by adding a six base DNA repeat on to the telomeric ends of chromosomes. As presented in the chapters of this volume, the mechanisms that regulate telomerase expression and activity are complex. Moreover, emerging data suggest additional roles for telomerase in the regulation of cell differentiation and survival. It is expected that this quite comprehensive volume will provide a valuable resource for graduate students and postdocs in the telomerase field and for established investigators in other fields who are beginning to study telomerase in their particular research program. With an increasing number of proteins being brought into the fold of telomerase research (e.g., DNA damage and repair response proteins, heat-shock proteins, and proteins in various signal transduction cascades) many new scientists are beginning to study this enzyme from novel vantage points.