DIED. Michael Landon, 54, boyishly handsome actor, best known for playing Little Joe Cartwright in Bonanza, and writer, director and producer of television hits; after a three-month battle with pancreatic and liver cancer; in Malibu, Calif. In 1957 Landon starred in the cult film favorite I Was a Teenage Werewolf. His part in Bonanza, which aired from 1959 to 1973, made him a household name. Landon subsequently starred in and wrote many of the episodes of Little House on the Prairie, solidifying a reputation for wholesome, if saccharine, family entertainment.