This century has already seen an unprecedented growth in practical attempts to understand and manage cancer. From its humble beginnings oncology has become not just a biological discipline in its own right but also a major international growth industry. The anecdotal reports from Paracelsus in 1531 to Rehn in 1895, and the cancer statistics of Tanchou in France and Rigoni-Stern in Italy during the 1840s, have grown into the sophisticated cancer epidemiology of today. This has been revealing an evergrowing compendium of physical, chemical, biological, and psychosomatic environmental associations in cancer genesis and development. For the proper testing of such associations, diverse experimental systems of animal, plant and human origins have been developed. At the human level, there have been notable advances in the classification, detection, treatment, and biology of cancer, and in public counselling and patient after-care. At the biospheric level, cancer has become recognized as a common affliction of all species of the Metazoa and Metaphyta, most probably from the early stages of their evolution. Overall, the ancient mysticisms and philosophizings about cancer have been slowly, over the centuries, becoming transformed into the practical approaches of today.