Legion is a novella written by Brandon Sanderson about Steven Leeds, a man with schizophrenia, or better yet, a poorly understood but advanced ability to generate a multitude of personae who co-exist in his world. He interacts with them and they interact with him. Steven does not "become" one of his personas, but can solicit their opinions or have them guide him in their expertise. They seem, for all intents and purposes, to be actual people but Steven and his personas fully understand that they are not real. The people that he conjures up are experts in languages, technology, weaponry and tactics, psychology, physics, and whatever else Steven requires in his existence.
What is interesting is that Steven relies on these people to work with him to unravel various cases and mysteries that come to his door. Steven's condition has allowed him to become a very wealthy man. When he really just wanted to be left alone, he was hounded by research groups that wanted to study him. The more he charged these people, the more money they threw at him. Steven is a man of contrasts. Jaded yet curious. Tired yet driven. Prideful yet humble.
In this story, Steven is approached about a mystery involving a camera that seemingly can take pictures of the past. The inventor of this technology has taken his prize and disappeared from the company that had backed his idea. The split occuring when the company saw only dollar signs while its inventor had a specific agenda. Sanderson poses some provocative questions about the use of such an invention that could bring absolute chaos to the world if it could be brought to bear to address certain questions. A highly enjoyable piece that is followed up with a full-length novel, Legion: Skin Deep that I have added to my reading list.