2.1.1.2 Commas in Essential & Nonessential Clauses

Essential, or defining, clauses should not be enclosed in commas. These clauses identify which person, text, object, or idea is meant.

• Crowley’s book Liber ABA: Magick remains one of his best-known works on ceremonial magic.
• The ritual that opens with the analysis of the keyword is often discussed in relation to Golden Dawn practice.
• The phrase “love under will” should not be separated from its Thelemic context.

Nonessential clauses, which add information but are not needed to identify the subject, should be set off with commas.

• Aleister Crowley, who received Liber AL vel Legis in 1904, became the first prophet of Thelema.
• The Book of Lies, which was first published in 1912, contains many short and deliberately cryptic chapters.
• The O.T.O. Gnostic Mass, which remains one of the best-known public rituals of Thelema, is the central ritual of Ordo Templi Orientis.