This document provides a classification of anticancer drugs into 9 main categories: 1) Alkylating agents which damage DNA like nitrogen mustards and platinum complexes. 2) Antimetabolites which are analogs of nutrients needed for cell growth such as methotrexate and 5-fluorouracil. 3) Antibiotics including anthracyclines derived from bacteria and bleomycin which is a quinone derivative. 4) Natural and semi-synthetic plant products that inhibit microtubules and topoisomerases, including taxanes, vinca alkaloids, and camptothecins. 5) Steroidal hormones and antagonists such as tamoxifen,