"Out of Time's Abyss" by Edgar Rice Burroughs is a science fantasy novel published in 1918. The final installment of the Caspak trilogy follows Bradley after his mysterious disappearance from Fort Dinosaur. Captured by the Wieroo—winged human creatures—he's taken to their island city where he meets Co-Tan, a woman from Caspak's most advanced tribe. Together they must escape and journey back across a prehistoric land where evolution unfolds through individual metamorphosis, connecting the fates of all who ventured into this lost world. (This is an automatically generated summary.)