Complex sentence: Feder was very interested in cryptozoology and ancient astronauts as a teenager, when a book called "Morning of the Magicians" about extraterrestrial aliens turned him on to what he describes as the nonsense in archaeology.
Split into simpler sentences: Feder was very interested in cryptozoology and ancient astronauts as a teenager. A book called "Morning of the Magicians" about extraterrestrial aliens, turned him on to the nonsense in archaeology.