In 2002, Sam Williams wrote Free as in Freedom, a biography of Richard M. Stallman. In its epilogue, Williams expressed hope that choosing to distribute his book under the GNU Free Documentation License would enable and encourage others to share corrections and their own perspectives through modifications to his work.
Free as in Freedom (2.0) is Stallman's revision of the original biography. While preserving Williams's viewpoint, it includes factual corrections and extensive new commentary by Stallman, as well as new prefaces by both authors written for the occasion. It is a rare kind of biography, where the reader has the benefit of both the biographer's original words and the subject's response.
Source files for Free as in Freedom (2.0), as well as a downloadable .pdf version, are found here: https://www.fsf.org/faif/