The Phillips Library holds 215 cyphering books. This collection contains 197 items, arranged in three series: Mathematics, Navigation, and Textbooks. Mathematics includes Arithmetic, Geometry, Trigonometry, and other subjects. The books are arranged chronologically within each series, with undated books falling at the end of the series. Many books contain more than one subject. There are also three textbooks included. Most of the cyphering books were created in New England, but one is from Canada and three are from England. Not all volumes are true cyphering books; a few are exercise books containing mathematical calculations with headings similar to the cyphering books. The Navigation books usually start with Geometry or Trigonometry and then cover different types of sailing, compass calculations, and a real or imagined log of a voyage.

An addendum, entitled "Summary of Ciphering Books at Phillips Library, Salem, Massachusetts" compiled by Nerida Ellerton and McKenzie Clements of Illinois State University in 2009, is attached to this Finding Aid. On the PEM Finding Aid, the number in brackets after the name of the cyphering book refers to the number on the addendum, which gives greater detail about each book that was examined. Additional items were found after Ms Ellerton and Mr. Clements left the library, so this collection includes titles not examined by them.