Samuel Liddell MacGregor Mathers (1854 – 1918), also known as the Evoker of Spirits, was one of the founders of the Hermetic Order of the Golden Dawn, alongside William Robert Woodman and William Wynn Westcott. He was also the husband of Moina Mathers.
Sometime towards the end of the 19th century, Mathers came in possession of the complete volume of the Book of Abraham. He attempted to translate it and was planning to publish the translated version, much to the disfavor of Westcott, who intended to keep its content a secret.
Despite their tensions however, both of them resolved to assassinate Woodman, mostly motivated by fear, since Mathers was able to see "beyond the corporeal", as expressed by Woodman himself, and thus perceived what he truly was. Even though the death of Woodman was decided, Mathers insisted, unlike Westcott, that they could still learn things from their victim.
After the assassination of Woodman, Mathers became the Imperator of the order for five years. After a conflict with Westcott however, he managed to make him leave the order, thus gaining the total control.
Later, Mathers isolated himself together with his wife Moina in Paris. Here, he let Aleister Crowley become an adept of the inner order and also met one of the Secret Chiefs who informed him that their partnership with the Hermetic Order of the Golden Dawn had ended because of the loss of William Robert Woodman.
In 1900, members of the order began revolting against him due to his dictatorial leadership even with Crowley turning against him in 1904. After his death in 1918, Moina Mathers continued to lead the order.
- Mathers knew about Woodman's continuing existence after his death. However, unlike his wife or Crowley, he was unable to see him.