Aliester Crowley's time spent at Boleskine house was due to the writings of a 15th century Jewish magician named Lamech.
Lamech's father Abraham had received the occult teachings of Abra-Melin and in 1458 had passed them on to his son, who in turn wrote them down in the book known as The Sacred Magic of Abra-Melin the Mage.
The book was later translated into Old French and a copy was eventually discovered by Samuel Liddel Mathers who translated it into English. Mathers, one of the founders of the Hermetic Order of the Golden Dawn, was captivated by it's content and passed on his enthusiasm to Crowley.
To follow the system of magic described by Abra-Melin required strict adherence to the details insisted upon in the book. Amongst other conditions it emphasized the importance on the correct ritual environment. Crowley did what he could to comply with the instructions in his rooms in Chancery Lane, London, but eventually decided that they were not really suitable, so he set about discovering the perfect location for the magical working.
He traveled the length an breadth of the country in his search - Abra-Melin demanded a seclude house with a north facing door, one which opened out onto a sand covered terrace. Why it should be so difficult to find such a dwelling is difficult to understand, but eventually, in August 1899, Crowley discovered the ideal place on the banks of Loch Ness and purchased Boleskine House.