Historical clue formulations

• American author whose life span closely coincided with Halley's comet visits — 2026-01-20
• "Life on the Mississippi" memoirist — 2025-04-04
• Mark of literary distinction — 2024-07-01
• "The father of American literature," per Faulkner — 2023-12-31
• Eponym for an annual prize for American humor — 2022-10-20
• Who wrote "When in doubt, tell the truth" — 2015-05-27
• "Is Shakespeare Dead?" writer — 2013-09-04
• Who said "Familiarity breeds contempt - and children" — 2013-02-03
• Author depicted next to a steamboat on a 2011 stamp — 2012-07-18
• "Huckleberry Finn" author — 2008-02-11
• Wit who wrote "When in doubt, tell the truth" — 2006-01-31
• "Tom Sawyer" author — 2003-05-12
• Aunt Polly's creator — 2000-07-19
• Injun Joe creator — 2000-02-09
• The Finn man — 1999-01-03
• "Pudd'nhead Wilson" writer — 1995-08-13
• "Following the Equator" author — 1994-06-15
• "Roughing It" writer — 1993-12-24