What is the fine-grained topic of the following text: Through interviews, road trips, and family documents, the author reconstructs a time peaking in mid-1950s Los Angeles when Huxley experimented with psychedelic substances, ran afoul of gatekeepers, and advocated responsible use of such hallucinogens to treat mental illness as well as to achieve states of mind called mystical. Only return the topic.
Aldous Huxley's experimentation with psychedelic substances in 1950s Los Angeles.