Mann Library's specific focus is on supporting the instruction, research, and extension programs of Cornell University's College of Agriculture and Life Sciences and College of Human Ecology.

In fulfillment of Mann's mission, the library's collection covers a wide range of cross-cutting basic and applied sciences, from biochemistry to animal science, genetics to plant breeding, nutritional sciences to food science, ecology and systematics to natural resources, human development and family studies to business management, environmental analysis to fiber science and apparel design.

As a land grant library for the State of New York, Mann is also open to the general public, and strives to make its electronic resources open to the public as well, although for contractual reasons certain databases are restricted to current members of the Cornell community.