Karl Alexander is an American writer. Born and raised in Los Angeles, he is the son and nephew of screenwriters—his father, William Tunberg, wrote the screenplay for Old Yeller, and his uncle, Karl Tunberg, wrote the screenplay for Ben-Hur—and has worked on a number of films himself. He is the author of Time After Time, which was adapted into a successful film of the same title in 1979, and several other novels. Jaclyn the Ripper, the sequel to Time After Time, was published in March 2011.