The Boston Athenæum is a membership library for use by its members, and also by scholars and researchers for short and long term projects. It is one of the oldest and largest membership libraries in the country.

Predating all American public libraries, the Boston Athenæum was founded in 1807 by a group of gentlemen who wished to provide themselves with " a reading room, a library, a museum and a laboratory." Past members of the Athenæum include John Quincy Adams, Ralph Waldo Emerson, Amy Lowell, Henry Wadsworth Longfellow, Daniel Webster, and Lydia Maria Child.

All members of the Boston Athenæum enjoy the privilege of borrowing books and the use of reference and book mailing services and have access to special collections. Members receive invitations to Athenæum events, which include lectures and book signings, art exhibitions, musical events, and children's programs; they also receive mailings of Athenæum Items, the Library newsletter, and discounts on many items in the bookstore.