Mammary Tumor Cell Cycle, Differentiation and Metastasis is the fifth volume since 1988 in a series designed to broadly examine current advances in the cellular and molecular biology of breast cancer. As in previous volumes, the editors have invited recognized experts in cutting-edge topics to provide a chapter focused on their area of research. The editors have turned to the researchers who study rodent models of the disease and to those who study the cellular and molecular basis of human breast cancer. The first section of the book is devoted to new mouse models of mammary development and tumorigenesis. The second section moves to studies of human breast cancer and focuses on receptors, signalling, and the cell cycle. The final section deals with defective tissue interactions in human breast cancer. We are now in a period of extremely rapid accumulation of data on the molecular and cellular biology of breast cancer. These findings are highlighted in chapters from Mammary Tumor Cell Cycle, Differentiation and Metastasis: Advances in Cellular and Molecular Biology of Breast Cancer.