Progress in Cell Cycle Research is a new annual series designed to be the source for up-to-date research on this rapidly expanding field. Review articles by international experts examine various aspects of cell division regulation from fundamental perspectives to potential medical applications. Researchers as well as advanced undergraduate and graduate students in cell biology, biochemistry, and molecular biology will benefit from this series.Progress in Cell Cycle Research is a new annual series designed to be the source for up-to-date research on this rapidly expanding field. Review articles by international experts examine various aspects of cell division regulation from fundamental perspectives to potential medical applications. Researchers as well as advanced undergraduate and graduate students in cell biology, biochemistry, and molecular biology will benefit from this series.Checkpoints in the Cell Cycle from a Modeler's Perspective (J.J. Tyson et al.). The Role of Rb in Cell Cycle Control (M. Hatakeyama, R.A. Weinberg). Regulation of p70s6k/p85s6k and Its Role in the Cell Cycle (R.B. Pearson, G. Thomas). MAP KinaseDependent Pathways in Cell Cycle Control (S.L. Pelech, D.L. Charest). Mechanism of Action of Rapamycin: New Insights into the Regulation of G1Phase Progression in Eukaryotic Cells (G.J. Wiederrecht et al.). Cell Cycle Control of DNA Replication (R. Fotedar, A. Fotedar). Cell CycleRegulated Transcription in Mammalian Cells (J. Zwicker, R. M?ller). The CLN Gene Family: Central Regulators of Cell Cycle Start in Budding Yeast (K. Levine et al.). Cyclin A: Function and Expression during Cell Proliferation (C. Desdouets et al.). The Role of Cyclin E in the Regulation of Entry into S Phase (K. Sauer, C.F. Lehner). p27KIP1: An Inhibitor of CyclinDependent Kinases (A. Koff, K. Polyak). Regulation of Cell Cycle Progression following lƒ¼