The attitude of biologists to the history of their discipline varies. For some, a hazy knowledge of the recent past is all that is necessary to provide an explanatory basis for their work. They take it for granted that everything of value from the less recent past has been appropriately incorporated into present-day thinking. Other biologists see history as an integral part of their research: the historical roots of accepted facts and theories help in the evaluation of present positions. These biologists bring to history their specialized knowledge, which can be an advantage, but often they also bring an agenda that biases what they investigate and how they present it. We illustrate this by describing our own foray into history, which was motivated by findings in cell biology that suggested that some accepted views about heredity and evolution were wrong.