Paul Lacroix, 1806-1884, was a prolific French author and journalist. Lacroix was an extremely prolific and varied writer. Over twenty historical romances alone came from his pen, and he also wrote a variety of serious historical works, including a history of Napoleon III, and the life and times of the Tsar Nicholas I of Russia. He also wrote many monographs on phases of the history of culture, and his works on bibliography were also extremely numerous. Lacroix is best known under his pseudonym of P. L. Jacob, bibliophile, or Bibliophile Jacob, suggested by the constant interest he took in public libraries and books generally. In 1885 he was appointed librarian of the Arsenal Library, Paris.