Recent molecular studies have greatly expanded the biological contexts where Top2 plays critical roles, including DNA replication, transcription and chromosome segregation. Although the biological functions of Top2 are important for insuring genomic integrity, the ability to interfere with Top2 and generate enzyme mediated DNA damage is an effective strategy for cancer chemotherapy. The molecular tools that have allowed understanding the biological functions of Top2 are also being applied to understanding the details of drug action. These studies promise a more refined ability to target Top2 as an effective anti-cancer strategy.