• The first letter of a call number represents one of the 21 major divisions of the LC System. In the example, the subject "Q" is Science.
• The second letter "E" represents a subdivision of the sciences, Geology. All books in the QE's are primarily about Geology.
  • Books in categories E, United States History, and F, Local U.S. History and American History, do not have a second letter.
  • Books about Law, K's, can have three letters, such as KFH, Law of Hawaii.
• All other subject areas will have call numbers beginning with one or two letters.
  • For most of the subject areas, the single letter represents books of a general nature for that subject area (i.e. Q - General Science or D - General World History).

Numbers after letters

• The first set of numbers in a call number help to define a book's subject.
• "534.2" in the example teaches us more about the book's subject. The range QE 500-625 are books about "Dynamic and Structural Geology."
• Books with call numbers QE534.2 are specifically "Earthquakes, Seismology - General Works - 1970 to Present"

Cutter numbers

Shelving and Locating

Items are shelved by call numbers - in both alphabetical and numerical order. The letters at the beginning of the call number are alphabetical. The numbers immediately following are in basic numerical order, i.e. 5 then 6, 50 is after 49 and before 51, and 100 is after 99. Thus,

The cutter numbers (A3, A31, Z4, C3, and A2 in the above example) are sorted first by the letter and then by the number as a decimal. For QD 1 A5, think of it as being QD 1 A 0.5, for QD 1 A332 read QD 1 A 0.332. Therefore,

Dates, volume and issue numbers, copy numbers, and other annotations are like an additional cutter number but are shelved by basic alphabetization (numbers alone come before letters):