The epigenetic machinery comprised of processes, such as DNA methylation, histone modifications, and noncoding RNA, contribute to heritable changes in gene expression or phenotype. These epigenetic changes do not involve changes in the actual DNA sequence and consist of an ever-expanding array of other epigenetic processes mediated by prions, Polycomb proteins, and higher-order chromatin organization, as well as many others. Innovative technology has driven the field of epigenetics, and the development of novel model organisms of epigenetics has also contributed to remarkable progress in epigenetics. Moreover, epigenetic processes are important in many functions that impact a vast number of organisms. Epigenetics has also influenced evolution and epigenetic epidemiology has demonstrated the intricate role between epigenetics and the environment. Finally, a number of human diseases, such as cancer, brain disorders, and metabolic syndromes have been associated with aberrations in epigenetic processes that now open a new area of advances in epigenetic therapy.