ASA's exploratory mission to Saturn starts out routinely enough--the spaceship Ringmaster is performing well, and the crew members are fully adjusted to their scientific and personal roles. Even the current set of sexual partnerships seems to be working out, at least for the moment. But when the crew spots a previously unknown "moon" that turns out to be a titanic artifact, the situation rapidly degenerates. Ringmaster is attacked, its crew is yanked bodily into space, and when Captain Cirocco Jones wakes up, she's alone, naked, hairless and cradled deep in a fluid-filled, womblike darkness.
Sensory deprivation, isolation and the "birth" trauma of crawling out of the "womb" and into the artifact's lush interior world unhinges most of Jones' crew. One ends up with a passionate crush on Jones, another loses most of his memories and a third becomes an emotional cripple. The others are altered more radically, some nearly beyond recognition. Jones herself seems unchanged, beyond a savage lust for adventure and a mysterious understanding of the language of one of the several local sentient species.
The artificial, self-contained world--eventually dubbed "Gaea"--shows signs of disrepair, an overgrown Eden fecund and vibrantly alive with a bizarrely creative ecology. But Jones finds the geography more daunting than the wildlife as she sets out to climb a support cable that stretches 600 kilometers to the top of the world. She hopes to find a control center or, better yet, an actual controller. If nothing else, she's determined to get an explanation. Or an apology.
Pulp physics
Titan's themes weren't particularly original when the book first came out in 1979. Arthur C. Clarke won the Hugo and Nebula awards for best novel just two years earlier for Rendezvous with Rama, and Larry Niven had also earned both awards for Ringworld in 1970. (Titan was a finalist for both awards, but won neither.) All three books have remarkable similarities in subject (gigantic alien artifact-worlds), scale (human-sized people trying to deal with a world-sized space) and style (personal drama vying with obsessively detailed hard science). And each of the three books set the stage for its own series of increasingly fantastical and xenogenic sequels.
But Titan's tone is uniquely vibrant and energetic, more fanciful and more believably human than its predecessors. A light, humorous touch pervades virtually all of Varley's work--along with a fascination with sexual roles and intelligent sexual politics--but this is an unusually straight-faced and straightforward book, distinctly unlike any of his later, more tangled novels. In many ways it's a simple quest story, epic in physical scale but mining the basic archetypes of 1940s SF pulp adventures, particularly the rough-and-ready hero and the scrutable-but-strange alien race. Only Varley's precise, free-flowing style and his incredibly sharp imagination keep this from becoming a parody or a pastiche.
Still, Titan leaves something to be desired in the face of Varley's other, more complex work--as huge as this book's scale becomes, as packed as it is with fascinating characters and fantastic descriptions, it still seems small and dry compared to the unbelievably ambitious books he went on to write over the course of the next two decades.