The A∴A∴ (Latin: Argenteum Astrum or Greek: Άστρον Αργόν, "Astron Argon", both literally; "Silver star", alternately, Latin: Arcanum Arcanorum, is a magical order created by Aleister Crowley in 1907 after leaving the Hermetic Order of the Golden Dawn. It is a Thelemic magical fraternity in which the holy book of the order is The Book of the Law. Its motto is: "The method of science, the aim of religion." While the A∴A∴ was not part of Ordo Templi Orientis, the O.T.O. did consider the A∴A∴ to be a close ally.
Various lineages of the A∴A∴ survive today that can be traced back to the founders Aleister Crowley and George Cecil Jones.
- Crowley, Aleister (1990). "An Account of A∴A∴" in The Equinox (Vol. I, No. 1). York Beach, Maine: Samuel Weiser.
- Wasserman, James (2004). "Introduction" in Aleister Crowley and the Practice of the Magical Diary. York Beach, ME: Redwheel/Weiser
- Crowley via Grady McMurtry lineage: Clerk Houses of Grady Louis McMurtry's A.'.A.'. Lineage
- Crowley via Jane Wolfe lineage: The Order A.'.A.'.
- Motta via Frater Adjuvo lineage: ASTRVM ARGENTVM
- Motta via David Bersson lineage: Castletower.org
- Motta via Ray Eales lineage: AATHELEMA
- A lineage noted by the OTO: outercol.org