Barrett, an Englishman, claimed himself to be a student of chemistry, metaphysics, and natural occult philosophy. He was known to be an extreme eccentric who gave lessons in the magical arts in his apartment and fastidiously translated Kabbalistic and other ancient texts into English.
He was very enthusiastic about reviving interest in the occult arts, and published a magical textbook called The Magus. Apart from possibly influencing the English occult novelist Bulwer-Lytton, the book gained little notice until it influenced Eliphas Levi.
The Magus also served as an advertising tool. In it Barrett sought interested people wanting to help form his magic circle. An advertisement in The Magus (Vol. 2, p. 140) refers to an otherwise unknown school founded by Barrett.