This course on cancer biology focuses on historical theories and cloning strategies put forth to comprehend carcinogenesis. The objective is to travel back in time to the period when all the pieces of puzzle such as chemical carcinogens, retroviruses and chromosomal mutations came together to reveal the grand scheme of cancer and propose the underlying criteria for cancer development. The highlights of this lecture series are the experimental methods developed during 1960s to 1990s which built the foundation for the current model of cancer which stems from two concepts namely- oncogenes and tumor suppressor genes.