Magick: Liber ABA, Book 4 by Aleister Crowley is a foundational, encyclopedic textbook on Western occultism, blending Eastern yoga, Qabalah, and ceremonial magic within the framework of Thelema. It teaches that "Magick is the Science and Art of causing Change to occur in conformity with Will," detailing practices like ritual invocation, meditation, and sexual magic to achieve spiritual enlightenment. This comprehensive work serves as a practical guide for the practitioner, covering meditation, rituals, and theoretical magical principles.