Excerpt from Wikipedia on ambient music:
...Beyond the major influence of Brian Eno, other musicians and bands added to the growing nucleus of music that evolved around the development of "Ambient Music". While not an exhaustive list, one cannot ignore the parallel influences of Wendy Carlos, who produced the original music piece called "Timesteps" which was then used as the filmscore to Clockwork Orange, as well as her later work Sonic Seasonings. Other significant artists such as Mike Oldfield, Jean Michel Jarre and Vangelis have all added to or directly influenced the evolution of ambient music. Adding to these individual artists, works by groups such as Pink Floyd, through their albums Ummagumma, Meddle and Obscured by Clouds. Other groups including Yes with their album Tales from Topographic Oceans, the Hafler Trio, Tangerine Dream, Popol Vuh, Can, and Kraftwerk have all added distinctive aspects to the growing and diversified genre of ambient music...