Thelema is a spiritual philosophy developed in the early 20th century by the British occultist Aleister Crowley. Central to Thelema is the concept of "Do what thou wilt shall be the whole of the Law," which emphasizes individual will and personal freedom. Followers believe that each person has a unique purpose or "True Will" that they should discover and pursue. Thelema incorporates elements from various religious and philosophical traditions, including Hermeticism, Kabbalah, and Eastern spirituality. Its practices often involve rituals, meditation, and the study of sacred texts, such as The Book of the Law, which Crowley claimed to have received through divine inspiration.