Complex sentence: Mysticism and a fascination with the paranormal imbued much of Koestler's later work and he became known for endorsing a number of paranormal phenomena, such as extrasensory perception, psychokinesis and telepathy.
Split into simpler sentences: Mysticism and a fascination with the paranormal imbued much of his later work. Koestler was known for endorsing a number of paranormal subjects such as extrasensory perception, psychokinesis and telepathy.