There has been a dramatic increase in the perception of the value of animal cell biotechnology to the research and manufacturing communities in recent years. This volume seeks to keep the reader up-to-date with this progress. This sixth and final volume in the series concentrates on the biology of animal cells in culture, giving special attention to the relationship between biology and the ability to use such cells productively. As the search continues for greater productivity, there is a need to understand the switches within cells that control expression. Additional abilities to manipulate those switches in a controllable manner are also required. In the last five years, considerable progress has been made in the elucidation of the mechanisms for cell signaling and control of gene expression. The 13 chapters of this volume are devoted to these subjects and to techniques in areas of particular concern in manufacturing circles. The achievements in the field to date are described in this book, which, together with its five companion volumes in the series, will provide a building block for the future development of animal cell biotechnology.