The excitement and curiosity surrounding epigenomics is driven by a growing community of researchers in a burgeoning field and the development of new technologies built on the backbone of genome sequencing projects. Research has shown that the adaptability and vulnerability of epigenetic states has profound effects on natural variation, the response of the genome to its environment and on health and disease. The aim of this volume is not to describe epigenomes, but rather to explore how understanding epigenomes tells us more about how biological systems work and the challenges and approaches taken to accomplish this. These contributions have attempted to integrate epigenomics into our understanding of genomes in wider context, and to communicate some of the wonders of epigenetics illustrated through examples across the biological spectrum.