Cellular proliferation, as a result of cell growth and cell division, is one of the most fundamental biological processes. Although there is a great deal which remains unclear, significant advances have been made in past decades in our understanding of the process and regulation of cell proliferation. There is considerable evidence that this understanding of different cells and cell proliferation behaviour provides useful information that may be of major importance in disease control, drug discovery, biomaterial development and medical device improvement. This book studies and discusses recent developments in the field of cell proliferation including: the controlling factors for cell proliferation; changes occurring in the cells; therapeutic effects of the biological molecules to the cells; and analysis of cell proliferation based on the quantal concept. Furthermore, the effects that biomaterials and drugs have on cell proliferation are also reviewed in this book.