The Green Tree Public Library began in 1942 with fifteen members of the Green Tree Woman's Club "Book Circle," later known as the Literary Group. These women each paid dues of $2.00. The dues were placed into a fund from which books were purchased and circulated within the group. In October of 1944, the group had the opportunity to purchase the library of the Paul Whitman Estate (Crafton) consisting of over 1,000 books for $20.00. Their goal had been to have a public library in the borough, so they borrowed the money from one of their husbands and received permission from Borough Council to use a room on the first floor of the Borough building.
Members of the book circle contributed $10.00 each for shelving and other supplies. The library's set-up then became a community effort. Two residents built the shelves at no charge. Lumber was bought from a local lumber company at great savings; a resident donated a desk, another a typewriter, and another had a stainless steel plaque made and installed on the front of the building. The librarian from Mt. Lebanon and a Green Tree resident who was a former librarian helped to sort and catalog the books. Letters to borough residents asking for book and monetary donations were delivered by the Boy Scouts. Up until this time, most expenses had been borne by the Woman's Club, and an "open house" was finally held on April 15, 1945.
A friends of the library group was organized in 1982. This is a support group to promote the use of the Library and provide additional items as needed.A part-time paid librarian was approved in 1983; and in 1989 the first full-time library director was approved. After meeting all criteria, the library qualified for state aid in 1986 and received their first matching grant of $500 for the purchase of books on the Constitution.When the new Municipal Center opened in 1990, the Library moved into much larger quarters and now has more than 38,000 volumes in its collection, along with books on CD, Playaways, DVDs, file materials, periodicals, newspapers, and Internet access for patrons.