Libraries have materials arranged in a specified order according to a library classification system, so that items may be located quickly and collections may be browsed efficiently. Some libraries have additional galleries beyond the public ones, where reference materials are stored. These reference stacks may be open to selected members of the public. Others require patrons to submit a "stack request," which is a request for an assistant to retrieve the material from the closed stacks.

Larger libraries are often broken down into departments staffed by both paraprofessionals and professional librarians.

Circulation handles user accounts and the loaning/returning and shelving of materials.
Technical Services works behind the scenes cataloguing and processing new materials and deaccessioning weeded materials.

Reference staffs a reference desk answering user questions (using structured reference interviews), instructing users, and developing library programming. Reference may be further broken down by user groups or materials; common collections are children's literature, young adult literature, and genealogy materials.

Collection Development orders materials and maintains materials budgets