The Gray Book, formally The Book of Gramarye, is a tome that contains an exact replica of the original Book of the Covenant, in which the Angel Raziel inscribed the runes, or Marks, the Nephilim are permitted to use.
There are only a few copies of the book, as each has to be specially made by Silent Brothers, particularly because it requires special paper to withstand the power of the runes. The High Warlock of Brooklyn, Magnus Bane, and every Institute each have their own copy of the book.
All young Shadowhunters learn the Marks from this book. Because of the fragility of the human mind, most Shadowhunter children grow up learning one rune from the Book at a time over a period of years. Reading too many runes at once would apparently give the reader a headache.
- Gramarye means 'magic' and 'hidden wisdom'. The "Book of Raziel" from Jewish mysticism is said to be a distorted version of the Gray Book.
- Despite its name, the Gray Book is in fact green.