This version of Dungeons and Dragons was authored by Gary Gygax between 1977 and 1979 as a complete rewrite of the full set of the original Dungeons and Dragons rules, with an eye towards resolving inconsistencies and presenting a canonical form of the game.
Called Advanced Dungeons & Dragons, or AD&D, it is now commonly called "1st Edition".
Random monster encounter charts featuring all the dungeon appropriate (i.e. no aquatic, sylvan, etc.) creatures listed in the 1st Edition Advanced Dungeons and Dragons Monster Manual, Fiend Folio, and Monster Manual II.