Robert J. Sawyer
Hominids, the first book of the Neanderthal Parallax, is a story of parallel worlds, ours and another in which Neanderthals, not homo sapiens, became the dominant intelligent species. In that world, Neanderthal civilization has reached heights of culture and science comparable to our own, but very different in detail and philosophy. During a risky physics experiment deep in a mine in Canada, a Neanderthal physicist, Ponter Boddit, is accidentally transferred to our universe, where another experiment is taking place in the same mine. He is captured and studied, alone and bewildered, a stranger in a strange land.
Back home, Ponter's research partner is left with a messy lab, a missing body, suspicious people all around and a murder trial that he can't possibly win because he doesn't know what happened. Talk about a scientific challenge! When luck, curiosity, imagination and inventiveness combine to save the day, it's not the end at all but a new beginning, with two worlds eager to learn more about what links them and what holds them apart. (From Tor)
Hominids won the Hugo Award for best novel of 2002.
From the book
The blackness was absolute.
Watching over it was Louise Benoît, twenty-eight, a statuesque postdoc from Montreal with a mane of thick brown hair stuffed, as required here, into a hair net. She kept her vigil in a cramped control room, buried two kilometers — "a mile an' a quarder," as she sometimes explained for American visitors in an accent that charmed them — beneath the Earth's surface.
From Hominids by Robert J. Sawyer ©2002. Published by Tor.