ABSTRACT
This chapter ventures some reflections based on my own experience as a biographer of Paul Langevin, a physicist of the early twentieth century, and Antoine-Laurent Lavoisier, a chemist of the late eighteenth century. Lavoisier and Langevin are still present in the French urban landscape. There are many streets, squares, public elementary schools or high schools named after them. To these names a number of popular images are attached. How to deal with these popular clichés when writing a biography? Shall we try to debunk them one after the other, or should we include them as part of the history of our subject?
