The Library uses the Library of Congress classification system. If you're not familiar with LC call numbers, they can seem a little confusing, but don't worry: here's a quick explanation of how they work.

Books are arranged first **alphabetically**, using the letters at the start of the call number: |
**LC**487 .C43 1994 |

Then **numerically**, by the numbers that come directly after the letter. These are read as **whole numbers**: in other words, 400 comes later than 43. |
LC**487** .C43 1994 |

Then **alphabetically** again, by the letter that comes after the decimal point: |
LC487 .**C**43 1994 |

Then **numerically** again, by the number that comes directly after that letter. These are read as **decimal numbers**: in other words: 55 comes later than 541. |
LC487 .C**43** 1994 |

There may be another letter-number combination after the one with the decimal point in front of it. If so, you read it the same way: first alphabetically by letter, and then numerically in decimal order. |
BX1795 .I57 **E83** 2000 |

The four-digit number at the end of the call number is the publication date of the item. |
LC487 .C43 **1994** |

Want to practice? Try this LC Call Numbers Quiz, provided by the librarians at Western Connecticut State University.

If you want to learn about which subjects are associated with which Library of Congress call numbers, see the Library of Congress Classification Outline.