Library of Congress (LOC) call numbers can look a little intimidating, but once you understand what all those letters and numbers mean, you should be able to find library items with ease.
- LOC call numbers are read one element (letter/letter combination or number) at a time, beginning to end (or top to bottom if printed vertically). When you're looking for an item, start with the initial letter (or pair of letters) and find each element in the order in which they appear.
- FIRST LETTERS: The first letter or set of letters tells you in what section of the library your item is found, and is arranged alphabetically. This means M comes first, then ML, then MT.
- FIRST NUMBERS: The number that follows is read as a whole number, so ML1 comes first, then ML 410, then ML2075.
- LETTERS AFTER THE DECIMAL: Like the first letter, these letters are also arranged alphabetically. ML410.C, therefore, comes before ML410.M.
- NUMBERS AFTER THE DECIMAL: As these numbers follow a decimal, they should be read as a decimal. This means .123 comes before .45, which comes before .6.
- Another letter/number combination can follow, which should be read the same way as the preceding one (remember: it's still after a decimal point!).
- YEAR (optional): The entire number can be followed by a four-digit number, which is a year, and which is read like a whole number.
Practice on this example call number:
Tips for searching using call numbers:
- Learn the call number for the subject you are interested in researching, or the genre of music you commonly look for. If you are studying Mahler, know that his biographies can be found under ML410 .M23. If you're interested in film music, be familiar with ML2075. If you need opera vocal scores, memorize M1503. This way you can browse those sections of the stacks without having to look up specific call numbers. Be aware, though, that books in these areas might also be located in other sections of the library, so don't rely solely on this method!
- HOWEVER, not all of our collection is browsable! What about books in the BookBot, ebooks, or books that are checked out? Use the library's advanced search function to browse call number ranges.
1. From the library homepage, click on the blue box with the magnifying glass next to the search box.
2. Select "advanced search"
3. Scroll to the bottom of the page and enter a call number range in the "Library of Congress Classification Range" fields. Make sure you choose an end number that will encompass any possible item within that range.