'The aim of scientific research is to develop hypotheses whose value is judged by the range of their application.' Boris Magasanik Research into the molecular genetic causes of cancer was founded by analyses of avian retroviruses. Two genes which have figured prominently in this history are the Myc and Myb oncogenes, which were initially identified as the cancer-causing principles of the avian retroviruses MC29 and AMV. Since their molecular cloning and the subsequent identification of their cellular homologs almost two decades ago, both oncogenes have been intensely studied, with >10 000 publications on Myc and >1400 publications on Myb currently found in the biomedical research literature. Surprisingly, despite the huge effort implied by this literature, defining the roles of Myc and Myb in neoplastic transformation has continued to challenge and frustrate researchers. Myc in particular continues to be a siren because of its central role in a large fraction of human cancers, and its function and regulation remains to a surprising degree unresolved. Ironically, while Myc research has stimulated diverse hypotheses with wide applications in molecular and cellular biology, understanding has lagged about Myc itself. Recently, however, the veils shrouding Myc and Myb may at last be lifting. The reviews collected here parse recent advances, but the aim is not so much to comprehensively survey the literature as to provide viewpoints that synthesize new and old findings, stimulate and extend hypotheses, reassess existing paradigms, and promote new insights.