In a library the collection is an organisational unit and the full compliment of information sources are called the libraries' collections.

Each library collection has a collections policy stating what is in the collection, why it's in the collection and how the collection is aiming to serve.

Typically library collections include:

  • In public/town libraries:
  • In university libraries
    • A teaching collection of materials to support the undergraduate teaching at the university. This typically includes desk copy and similar services, since these materials have surges of interest and must be rationed.
    • A research collection, with all the key books, journals and documents in all the areas of active research being conducted at the university.
    • Special collections. Special collections typically start a private collections of researchers who collection comprehensive collections in their own narrow field and then donate the collection to the university on condition that it is maintained. Once part of the university library the special collection becomes a highlight to be cultivated and promoted, since well-known and well-studied special collections can bring new researchers and research funding to the university. Most universities have a special collection related to local history or regional history.
    • A light reading collection. Many university libraries have a donation-only light reading collection for the enjoyment of the university students and staff. Novels are donated to the collection but no new books are bought for it from central funding.