When used in the context of reproduction of living cells the phrase "cell growth" is shorthand for the idea of "growth in cell populations by means of cell reproduction." During cell reproduction one cell (the "mother" cell) divides to produce two daughter cells. Cell proliferation, which depends on the intimately linked processes of growth and division, is a fundamental systems-level attribute of all life forms. The precise regulation of proliferation in response to internal and external cues is critical for development, tissue renewal and evolutionary fitness, while the disregulation of cell proliferation underlies a variety of human diseases, most notably cancer and ageing. Historically, breakthroughs in our understanding of cell growth and division have derived from cross-fertilisation of results and ideas from researchers studying a wide range of model organisms, from yeast to humans. The basis for cell proliferation entails the control of key signalling and cell cycle regulators through transcriptional, translational, post-translational, genetic and epigenetic mechanisms. Indeed, many conceptual breakthroughs in cell regulation have derived from analyses of basic cell cycle mechanisms. This book presents the latest research in the field.