Original: Kenneth Grant has written several books on Thelema and the occult, such as The Magical Revival, Aleister Crowley and the Hidden God, Outside the Circles of Time, and Hecate's Fountain.
Simplified: Kenneth Grant, who has written many books on Thelema and the occult, such as The Magical Revival, Aleister Crowley and the Hidden God, Outside the Circles of Time, and Hecate's Fountain.