On the Cover: The stored informtion in our DNA is susceptible to chemical modifications that constitute epigenetic alterations of the genome. DNA can be modified by cytosine methylation, and the histone component of chromatin can be modified by a number of post-translational modifications which control gene expression. These epigenetic processes control the packaging and function of the human genome and contribute to normal and pathologic states, such as aging, mental health, and cancer. Epigenetic alterations to DNA alter the structure of chromatin anf the expression patterns of genes and are inherited along with the genetic information contained within genes. The epigenetic signature imposed upon chromatin often results in silencing of expression of genes that normally contril cellular proliferation, and is increasingly recognized as a powerful component in driving tumor initiation and expression. In order to fully understand the regulation of stored information in our DNA, it will be necessary to define epigenetic states and how these are altered during disease initiation and progression. In this issue, Drs. Jones and Martienssen and colleagues report strategies discussed at a special AACR workshop on the human epigenome. This report makes a very strong detail argument for the undertaking of a Human Epigenome Project. For details, see the ariticle by Jones and Martienssen on page 11241 of this issue. (Cover figure modified and reproduced with the permission of Thomas Jenuwein and the Cold Spring Harbor Laboratory Press.)