The purpose of the Understanding the Rules of Life: Epigenetics (URoL:Epigenetics) program is to enable innovative research and to promote multidisciplinary education and workforce training in the broad area of epigenetics. The URoL:Epigenetics program is a wide collaboration across Directorates/Offices within the National Science Foundation with a focus on understanding the relationship between epigenetic mechanisms associated with environmental change, organismal phenotype, and resultant robustness and adaptability of organisms and populations. Successful projects of the URoL:Epigenetics Program are expected to use complementary, interdisciplinary approaches to investigate how epigenetic phenomena lead to emergent properties that explain the fundamental behavior of living systems. Ultimately, successful projects should identify general principles (“rules”) that underlie biological phenomena within or across scales of size, complexity (e.g., molecular, cellular, organismal, population) and time (from sub-second to geologic) in taxa from anywhere within the tree of life, including humans. URoL:Epigenetics projects must integrate perspectives and research approaches from more than one research discipline (e.g., biology, chemistry, computer science, engineering, geology, mathematics, physics, social and behavioral sciences).The interdisciplinary scope of URoL:Epigenetics projects also provides unique training and outreach possibilities to train the next generation of scientists in a diversity of approaches and to engage society more generally. Letter of Intent Deadline: December 20, 2019.