Call numbers are organized by subject. When you find your book on the shelf, take a minute to look around to see if there are others that may be of interest.
Most of the Library uses the Library of Congress Classification System.
PS3551 | The numbers following the letter(s) are read as a whole number (three thousand five hundred and fifty-one). PS3551 would come before PS3650. |
.5 | If there are additional numbers immediately after the whole number, you should treat them as a decimal.PS3551.5 would come between PS3551 and PS3552. |
.N257 U53 |
For the next part of the call number, go to the letter(s) and then treat the number(s) as a decimal. .N257 U53 would come between .N257 U450 and .N257 U6. |
1999 | The final number, if included, is the year of publication.This book was published in 1999. |
Some of the John Crerar Library's collections on the Lower Level are shelved by the Dewey Decimal Classification System.
630.51 | The number in front of the decimal is read as a whole number (six hundred and thirty), then treat the rest as a decimal. 630.4 would come between 630.31 and 630.52. |
P884 | For the final number, go to the letter first and then read the rest as a whole number. P884 would come between P883 and P885. |
Some materials from the Library's East Asian Collection are shelved by the Harvard Yenching system.
8911 |
The numbers are read as a whole number (eight thousand nine-hundred and eleven). 8911 would come before 8950. |
.5 | If there are additional numbers immediately after the whole number, you should treat them as a decimal. 8911.5 would come between 8911 and 8912. |
4426 | The next number is also read as a whole number. |
Some government publications at D'Angelo are shelved by the Superintendent of Documents Classification System (SuDocs). Boston College has a nice guide to reading SuDocs numbers.
The Library uses two classification systems for legal materials, Benyon K and the Library of Congress K classification. To distinguish the two K call numbers, we precede LC call number with XX (example, XXKF 1000). Both call numbers are read just as you would any other Library of Congress call numbers.