The central aim of the OTO is to promulgate the concepts from in the Holy Books of Thelema.  The essential difference between ours and other paths to enlightenment is the concept of Will, the importance of establishing one's direct relationship with God in order to discover the unique path that will further strengthen that relationship.  This concept is expounded in the Liber Al (the foremost of the Holy Books) with such quotes as:

"Do what thou wilt shall be the whole of the Law."

"Thou hast no right but to do thy will."

Borne out of the Masonic traditions at the turn of the 20th century, Aleister Crowley introduced a series of similarly staged initiations into the OTO to help its members come to realisation of their "True Will."

There are three stages of initiation and everyone is entitled to take initiation through the first stage, called the "Man of Earth" degrees.  The only requirement is that you accept the Book of the Law, i.e. the concept of Thelema.

The OTO is a dues paying organisation and fees are payable to cover initiations and administration costs.