Crowley wrote down more Thelemic Holy Books during the last two months of the year, including "Liber LXVI", "Liber Arcanorum", "Liber Porta Lucis, Sub Figura X", "Liber Tau", "Liber Trigrammaton" and "Liber DCCCXIII vel Ararita", which he again claimed to have received from a preternatural source. In need of money, he launched a series of court cases against people whom he believed to have libelled him, some of which proved successful. In their subversive powers, he saw the possibility of an annihilation of old religious traditions, and the creation of a void that Thelema, subsequently, would be able to fill. Announcing the start of the Æon of Horus, The Book declared that its followers should "Do what thou wilt" and seek to align themselves with their True Will through the practice of ceremonial magic.

In October 1897, a brief illness triggered considerations of mortality and "the futility of all human endeavour", and Crowley abandoned all thoughts of a diplomatic career in favour of pursuing an interest in the occult. Eckenstein joined him later in 1900, and together they climbed several mountains, including Iztaccihuatl, Popocatepetl, and Colima, the latter of which they had to abandon owing to a volcanic eruption. At the heart of this text was the message, “ Do what thou wilt shall be the whole of the law; love is the law, love under will. Numerology has been used for thousands of years to help determine meaning in the greater cosmic plan.She bequeathed the original paintings of her Tarot cards to fellow Thelemite Gerald Yorke, who in turned placed them with the Warburg Institute along with much other Crowley material that he had collected over the years.

Heading on a honeymoon to Paris, Cairo, and then Ceylon, Crowley fell in love with Rose and worked to prove his affections.T.O's British branch, the Mysteria Mystica Maxima (MMM), and at a ceremony in Berlin Crowley adopted the magical name of Baphomet and was proclaimed "X° Supreme Rex and Sovereign Grand Master General of Ireland, Iona, and all the Britons". Crowley spent much of his time at university engaged in his pastimes, becoming president of the chess club and practising the game for two hours a day; he briefly considered a professional career as a chess player. For Crowley, sex was treated as a sacrament, with the consumption of sexual fluids interpreted as a Eucharist. Arriving in New York City, he moved into a hotel and began earning money writing for the American edition of Vanity Fair and undertaking freelance work for the famed astrologer Evangeline Adams.

In roughly 1938, Crowley’s student, Lady Frieda Harris, suggested a re-imagined tarot based on the Book of the Law. He is usually in ragged clothing, often carries a staff, and is also portrayed with the classic jester’s hat with bells. Biographer Lawrence Sutin noted that Crowley exhibited "courage, skill, dauntless energy, and remarkable focus of will" while at the same time showing a "blind arrogance, petty fits of bile, [and] contempt for the abilities of his fellow men". Professing to be of Irish ancestry and a supporter of Irish independence from Great Britain, Crowley began to espouse support for Germany in their war against Britain.On 1 December 1947, Crowley died at Netherwood of chronic bronchitis aggravated by pleurisy and myocardial degeneration, aged 72. The Rider Waite fool is gazing into the sky above, about to step off a cliff — a little dog tries to warn him. In October and November 1910, Crowley decided to stage something similar, the Rites of Eleusis, at Caxton Hall, Westminster; this time press reviews were mixed. Crowley enjoyed being outrageous and flouting conventional morality, [264] with John Symonds noting that he "was in revolt against the moral and religious values of his time".

R. Stephenson meanwhile wrote The Legend of Aleister Crowley, an analysis of the media coverage surrounding him.An underlying theme in many of his writings is that spiritual enlightenment arises through transgressing socio-sexual norms. he met with Charles Stansfeld Jones and Wilfred Talbot Smith to discuss the propagation of Thelema on the continent. Crowley's father was particularly devout, spending his time as a travelling preacher for the sect and reading a chapter from the Bible to his wife and son after breakfast every day. To [Crowley] the greatest aim of the magician was to merge with a higher power connected to the wellsprings of the universe, but he did not trouble himself too much to define that power consistently; sometimes it was God, sometimes the One, sometimes a goddess, and sometimes one's own Holy Guardian Angel or higher self. Aquarius and Aries are therefore counterchanged, revolving on the pivot of Pisces, just as, in the Trumps VIII and XI, Leo and Libra do about Virgo.