In Caverns Below

Mining engineer Frank Comstock takes a job checking out the integrity of a shut-down mine in Nevada. He gets his answer when the mine caves in, plunging him far underground into a network of tunnels occupied by two warring races of unknown chalk-skinned humans! Frank finds himself in a world of trouble as he gets caught in a battle, captured by one side, taken under the protection of a curious professor, and integrated into this strange society. Frank finds Wu a bizarre place. Diplomats invent reasons to continue a pointless war, just to protect the jobs and dividends of arms producers. Prosperity is measured in the amount of excess production they need to destroy. Workers and owners regularly clash, and neither side comes out ahead. Plus, there are differences from the land he's left behind! (Goodreads)