John Varley has written several novels and numerous short stories. Many of these stories are set a century or two after a race of mysterious and omnipotent aliens, the Invaders, have almost completely eradicated humans from the Earth (they regard whales and dolphins to be the superior Terran lifeforms and humans as only a dangerous infestation). But humans have inhabited virtually every other corner of the solar system, often through the use of wild biological modifications learned, in part, by easvesdropping on alien communications. His detailed speculations on the ways humans might use advances in biological science were revelatory in the 1970s when his story collection The Persistence of Vision was released. The title story won the Hugo and Nebula awards. "Overdrawn at the Memory Bank", a story from the Persistence of Vision collection, was adapted and televised for PBS in 1983. Also two of his short stories ("Options" and "Blue Champagne") were adapted into episodes of the short-lived 1998 Sci-Fi Channel TV series Weslcome to Paradox. Varley spent some years in Hollywood but the only tangible result of this stint was the film Millennium Varley is often compared to Robert A. Heinlein. Two of his connected novels, Steel Beach and The Golden Globe, contains a society evolved from a prison colony on Pluto and a second society evolved from it on Pluto's moon, Charon. Unlike Heinlein's lunar society, Varley's convict society is a cross between the mafia and the yakuza. Varley is noteworthy for the frequent prominence of female characters, unusual in science fiction, and especially so among male authors of hard science fiction. This prominence is visible not only in his Eight Worlds history where sex changes are routine, but in his other works as well. The idea of routine sex changes is also an example of the sexual themes that color his works without dominating them.