Nicolas Werth is a French historian.

The Black Book of Communism: Crimes, Terror, Repression is a 1997 book by Stéphane Courtois, Andrzej Paczkowski, Nicolas Werth, Jean-Louis Margolin, and several other European academics documenting a history of political repression by communist states, including genocides, extrajudicial executions, deportations, and deaths in labor camps and artificially created famines. The book was originally published in France as Le Livre noir du communisme: Crimes, terreur, répression by Éditions Robert Laffont. In the United States, it was published by Harvard University Press, with a foreword by Martin Malia. The German edition, published by Piper Verlag, includes a chapter written by Joachim Gauck. The introduction was written by Courtois. Historian François Furet was originally slated to write the introduction, but he died before being able to do so.