David Baltimore: Scientist, leader, and mentor.

Fifty years ago, at the remarkably young age of 37, David Baltimore received the Nobel Prize (with Howard Temin and Renato Dulbecco) for "discoveries concerning the interaction between tumor viruses and the genetic material of the cell." David was a prolific scientist whose work spanned many topics, but he was first and foremost a virologist. His recent passing invites us to reflect on a remarkable intellectual trajectory that began with seminal discoveries in virology, broadened to encompass major advances in cancer biology and immunology, and culminated in a legacy-sustained by the many scientists he trained-that will continue to shape modern biomedicine for years to come.