Kinds Of Immortality

Fictional immortals live either through history or through an indefinite future. Poul Anderson's Hanno does both. Most "immortal" characters are really "a-mortal" although two exceptions are Hob Gadling and Captain Jack, both immune not only to disease or aging but also to accident or violence. Anderson's Anson Guthrie and his second wife are endlessly downloaded, then resurrected, thus joining the ranks of their creator's "immortals." In Anderson's earlier "Lord Of A Thousand Suns," an alien personality was downloaded, then imposed not on a newly constructed organism but on an already existing one. See here. For more on that story, see here.

In Robert Heinlein's Future History, Professor Pinero, having invented and applied either the "baronoviameter" or the "chronovitameter"(see here), accurately predicts the date and time of death of any individual but refuses to give a reading to Lazarus Long who, we infer, will continue to lie indefinitely. James Blish's John Amalfi does live indefinitely - until the end of the universe which, for narrative convenience, is brought unexpectedly close to the present. Will Hanno, Hugh Valland and Guthrie live until the end of the universe in their timelines? Statistics should catch up with Hanno and Valland but Guthrie has the advantage that he exists as multiple downloads.