William Bast was a writer best known for co-creating The Colbys, a spinoff of ABC’s top-rated soap opera Dynasty. The series ran from 1985-1987 and featured Charlton Heston, Katharine Ross, Barbara Stanwyck and Ricardo Montalban. Bast developed, wrote and produced the show about the wealthy Colby family alongside partner Paul Huson. Aaron Spelling served as an executive producer.

Bast was nominated for an Emmy Award in 1977 for writing the television movie The Man in the Iron Mask, starring Richard Chamberlain. In 1984 he received a WGA award for writing the miniseries The First Olympics: Athens 1896, which he shared with co-writer Charles Gary Allison.

His other work in television included writing for the series Bus Stop, National Velvet, The Outer Limits, The Alfred Hitchcock Hour, The Fugitive, Perry Mason, Mod Squad, The Waltons, The New Perry Mason and Hawaii Five-O. He also adapted the ABC TV movie The Legend of Lizzie Borden, as well as The Scarlet Pimpernel for CBS, starring Anthony Andrews and Ian McKellen. Additionally, he created, wrote and produced the series Tucker’s Witch, about a married couple who are private detectives, one of whom wields supernatural powers.

He also wrote feature films, including The Valley of Gwangi, Hammerhead and Harold Robbins’ The Betsy, which starred Laurence Olivier and Robert Duvall.

Bast was a close friend of actor James Dean, whom he met after he moved to Los Angeles to study theater at UCLA. After Dean's death in 1955, Bast wrote the well-received James Dean: A Biography, published in 1956. Fifty years later, he published a more candid book about their friendship titled Surviving James Dean.

He died May 4, 2015, in Los Angeles. He was 84.