Increased heavy metal exposure is an abiotic and mainly anthropogenic factor. Environmental contamination with these elements has increased over the past decades, which has aroused attention from researchers responsible for contamination diagnosis, environmental protection and ecological remediation. My book focused on the question if an excess of trace elements (micronutrients) such as copper (Cu2+) and zinc (Zn2+) and the heavy metal cadmium (Cd2+) could change the epigenetic regulation of the genome in the model plant Arabidopsis thaliana.