Shadow Hunters: The Nest Gatherers of Tiger Cave documents a fascinating way of life. Authors Eric Valli and Diane Summers spent over a year in vast sea caves scattered along Thailand's southwestern coast where they recorded the lives of men practicing an ancestral craft: harvesting the principal ingredient of bird's-nest soup. Risking 400-foot falls, these nimble hunters clamber barefoot up a web of bamboo poles and vines lashed to stalactites to reach delicate nests for which Hong Kong restaurateurs will pay up to $1,000 a pound.

With the publication of Shadow Hunters, Valli and Summers, authors of Honey Hunters of Nepal, have once again shed light on the traditions of a unique and little-known trade. As they climbed with the hunters, sharing the same risks and hardships, they created uncommon bonds of trust which allowed them to photograph moments of great intimacy and danger. The nest gatherers believe that spirits, demons, and the ghosts of hapless climbers dwell within the caves. Anyone seeing the eerie and mysterious photographs in Shadow Hunters will understand why.