This book presents an elucidative account on the mechanisms and fundamental concepts of DNA Methylation. Alterations in the normal DNA methylation processes can inflict serious results on embryonic growth and are related with congenital flaws, autoimmunity, aging and malignant transformation. The prime objective of this book is to deliver information about the significance of methylation process in human health and disease. This book encompasses the elementary mechanism of DNA and protein methylation, with emphasis on undergraduate and graduate biomedical students and researchers working in the field of epigenetics. It provides an account on background and latest information in the field of methylation. It also provides readers with both traditional and relevant recent developments in this field, indicating new pathways where questions remain unanswered.