Shannon Gilligan began working with Choose Your Own Adventure in 1981, when she was hired to project manage the development of a Choose Your Own Adventure: Escape into a video game for the first Atari console. She continued her involvement with Choose by writing several bestsellers in the series, including Cup of Death, Ghost Island, and The Lake Monster Mystery. In the early 1990s, Gilligan was evangelized by Apple to develop software for the Mac. Her mystery game "Who Killed Sam Rupert?" subsequently became the first game to include Quicktime, the earliest commercially distributed video playback software for personal computers. Gilligan continued to develop software for the Mac and the PC for several years, and produced and directed Comic Creator, voted Best Software of the Year by People Magazine in 1995. In 2006, she co-founded Chooseco LLC with R. A. Montgomery, as a purpose-built publishing house for the re-launch of the Choose Your Own Adventure series. Gilligan has overseen the sales of over 15 million copies of CYOA in the past decade, while expanding licensing of the Chooseco catalog into film, board games, and now interactive audiobooks. In 2012, Gilligan conceived and wrote the script for the prototype of Choose Your Own Adventure Choose 'Toons, interactive cartoons based on Ray's bestselling title for younger readers, Your Very Own Robot. Since the series re-launch, Gilligan has written several more CYOA bestsellers including Princess Island and Unicorn Princess.