DNA methylation is an epigenetic process that occurs when a methyl group binds to one of DNA's four bases, cytosine. These changes are responsible for controlling the activity of genes by turning them off. DNA methylation patterns differ dramatically between healthy and diseased tissue and thereby can serve as biomarkers, opening a window into earlier detection of disease. Editor Martin Widschwendter (Institute for Women's Health, University College London) emphasizes that, "The concept of early detection of tumors before they spread and become incurable, represents one of the most important challenges in reducing the impact of the growing burden of cancer worldwide...Altered patterns of DNA methylation can be detected with high sensitivity, potentially providing us with diagnostic, prognostic and predictive information, and can be reversed by appropriate drug treatment. These possibilities make cancer epigenetics a most exciting field of current translational research." This book contains ten articles that explore the details and challenges of cancer epigenetics.