A Novella by Brandon Sanderson called Legion is available as a free audiobook from audible available to US accounts not sure about other regions
Stephen Leeds, AKA 'Legion,' is a man whose unique mental condition allows him to generate a multitude of personae: hallucinatory entities with a wide variety of personal characteristics and a vast array of highly specialized skills. As the story begins, Leeds and his 'aspects' are drawn into the search for the missing Balubal Razon, inventor of a camera whose astonishing properties could alter our understanding of human history and change the very structure of society. The action ranges from the familiar environs of America to the ancient, divided city of Jerusalem. Along the way, Sanderson touches on a formidable assortment of complex questions: the nature of time, the mysteries of the human mind, the potential uses of technology, and the volatile connection between politics and faith. Resonant, intelligent, and thoroughly absorbing, Legion is a provocative entertainment from a writer of great originality and seemingly limitless gifts.