Nathaniel Bacon (1598–1676), also known under the assumed name of Southwell, (Sotwel, or Sotvellus in Latin), was an English Jesuit who served in Rome from 1647 until his death as Secretary of the Society of Jesus. He produced an encyclopedia in folio, Bibliotheca Scriptorum Societatis Jesu (Rome, 1676). This was a continuation of the bibliographies of Pedro de Ribadeneira and Philippe Alegambe.
In the 19th century it was updated by Belgian Jesuits Augustin de Backer and Carlos Sommervogel as Bibliothèque de la Compagnie de Jesus, a standard reference work.