Wiki has this to say about 'The Beast" and his assocciation with the order...
Involved as a young adult in the Hermetic Order of the Golden Dawn, he first studied mysticism with and made enemies of William Butler Yeats and Arthur Edward Waite. Like many in occult circles of the time, Crowley voiced the view that Waite was a pretentious bore through searing critiques of Waite's writings and editorials of other authors' writings. In his periodical The Equinox, Crowley titled one diatribe, "Wisdom While You Waite", and his note on the passing of Waite bore the title, "Dead Waite".
His friend and former Golden Dawn associate, Allan Bennett, introduced him to the ideas of Buddhism, while Samuel Liddell MacGregor Mathers, acting leader of the Golden Dawn organization, acted as his early mentor in western magic but would later become his enemy. Several decades after Crowley's participation in the Golden Dawn, Mathers claimed copyright protection over a particular ritual and sued Crowley for infringement after Crowley's public display of the ritual. While the public trial continued, both Mathers and Crowley claimed to call forth armies of demons and angels to fight on behalf of their summoner. Both also developed and carried complex Seal of Solomon amulets and talismans.
In 1899, Crowley acquired Boleskine House, in Foyers on the shore of Loch Ness in Scotland. In a book of fiction, titled Moonchild, Crowley later portrayed Mathers as the primary villain, including him as a character named SRMD, using the abbreviation of Mathers' magical name. Arthur Edward Waite also appeared in Moonchild as a villain named Arthwaite, while Bennett appeared as the silent, monkish Mahathera Phang. While he did not officially break with Mathers until 1904, Crowley lost faith in this teacher's abilities soon after the 1900 schism in the Golden Dawn (if not before). Later in the year of that schism, Crowley travelled to Mexico and continued his magical studies in isolation. Crowley's writings suggest that he discovered the word Abrahadabra during this time.
In October 1901, after practicing Raja Yoga for some time, he said he had reached a state he called dhyana—one of many states of unification in thoughts that are described in Magick (Liber ABA). 1902 saw him writing the essay Berashith (the first word of Genesis), in which he gave meditation (or restraint of the mind to a single object) as the means of attaining his goal. The essay describes ceremonial magick as a means of training the will, and of constantly directing one's thoughts to a given object through ritual. In his 1903 essay, Science and Matter, Crowley urged an empirical approach to Buddhist teachings.