Jim Byrnes is a screenwriter who has written extensively for television shows since 1960, including Daniel Boone, Gunsmoke (44 episodes as assistant story consultant or writer), Bearcats!, How the West Was Won (developed for television and wrote), Swamp Thing and Walker, Texas Ranger, as well as writing and producing numerous TV movies from the the mid-'70s through to the mid-'90s, mostly Westerns. Byrnes wrote an unfilmed story for the 1974 Planet of the Apes TV series, titled "The Trek".