As noted above, Hetzel and Verne generated a sequel of sorts to this novel: L'Île mystérieuse (The Mysterious Island, 1874), which attempts to round off narratives begun in Twenty Thousand Leagues Under the Seas and Captain Grant's Children, a.k.a. In Search of the Castaways. While The Mysterious Island attempts to provide additional background on Nemo (or Prince Dakkar), it is muddled by irreconcilable chronological discrepancies between the two books and even within The Mysterious Island itself.
Verne returned to the theme of an outlaw submarine captain in Facing the Flag (1896). This novel's chief villain, Ker Karraje, is an unscrupulous pirate acting for personal gain, he does not have Captain Nemo's nobility of character. Though published in several editions and translated, Facing the Flag did not achieve the lasting popularity of Twenty Thousand Leagues.
