The fear of death follows from the fear of life. A man who lives fully is prepared to die at any time.

We searched Mark Twain's collected works, published letters, notebooks, speeches, and documented interviews, including the archival tools of the Mark Twain Project, and found no primary source containing these exact words. One research pass raised Robert Anthony, the self-help author, as a possible originator, but no specific title, edition, or page could be pinned to him, so that remains a lead rather than a documented alternative source. A live database check surfaced several real books quoting the line — including James Bishop's "Epitaph For A Desert Anarchist" (1995), Marie Carter's "The Trapeze Diaries" (2008), and a 2010 Congressional Record entry — but these are all late-20th and 21st-century usages that recirculate the sentence without tracing it to Twain, and one even attaches it to Twain jokingly ("Missouri Grits"), which is not evidence of authorship. The phrasing does carry a more earnest, existential-motivational register than Twain's characteristically wry, ironic style, which fairly raises doubt, but stylistic mismatch alone is not the citable competing origin our policy requires. Absent both a primary Twain source and a documented alternative author or datable earlier instance, we cannot verify it, cannot call it misattributed, and see no genuine authorship dispute among credible sources — only widespread modern recirculation under Twain's name. On the balance of the evidence, this quote is commonly credited to Mark Twain but unsupported by any primary source, and its status is attributed.