The story sounded so strange that many people initially took it for a hoax: A tiny humanlike female, with a brain the size of a chimp’s and a body the size of a hobbit’s (as news stories loved to point out), was living on the remote Indonesian island of Flores just 18,000 years ago. The remains of this three-foot-tall marvel and her kin, dubbed Homo floresiensis, now has anthropologists racing to rework their evolutionary trees—and battling with a key researcher who has taken possession of the bones, seeking to prove the whole discovery a mistake.