Participating for the first time in a Lindau meeting, Renato Dulbecco began his lecture by explaining two different ways to study cancer: One as a medical doctor looking for causes, symptoms and treatments and the other as a biologist looking into the primary processes in the cell. With his background as both a medical doctor and biologist, Dulbecco could have chosen any of these two ways for his career, but at some point he decided to follow the second one. Since Alfred Nobel in his will wrote that one of his five prizes should be given in physiology or medicine, Dulbecco might very well have received a Nobel Prize even if he had chosen the first way! But with his choice of biology, the Lindau lecture concentrates on the topic that he and his student Howard Temin received their Nobel Prizes for (together with David Baltimore): The interaction between tumour viruses and the genetic material of the cell. That viruses can cause cancer in animals was shown in the early years of the 20th century by Peyton Rous, but his findings were not accepted by the scientific community until the 1950’s. At age 87, Rous finally received a Nobel Prize in Physiology or Medicine in 1966, after one of the longest waiting periods in the history of the Nobel Prizes! Since Alfred Nobel wrote in his will that the prizes should be given for work done during the preceding year, a frequent question is how the Prize-Awarding Institutions can wait for such a long time. The answer is that they didn’t accept the task of awarding the prizes until some more flexible rules were laid down, rules that can be found in the Statutes of the Nobel Foundation. At the time of Dulbecco’s lecture, the study of tumour viruses had made several important breakthroughs, in particular due to the methods of genetic engineering. So it must have been inspiring for Dulbecco to have in the audience two of the pioneers of this technique, Werner Arber and Hamilton Smith. Anders Bárány