In 1915 the East Hampton School District appropriated $400 to augment the Library's modest income. The Library, in this period before Guild Hall was founded, was the center of cultural life in the village. Lectures, concerts, club meetings, and book groups all took place at the Library. The old handwritten Minutes of monthly meetings of the Board of Managers of this period tell the story of trying to meet the needs for staff, equipment and new books on a very small income. A typewriter in 1919 and a telephone in 1926 were long studied acquisitions. 

In 1930 Mary and Lorenzo Woodhouse added to their original gift by giving a new Board Room and connecting Cloister. That same year Mary Gardiner Thompson and Jonathan T. Gardiner built the Gardiner Memorial Room to house the recently donated Pennypacker Long Island Collection. It was an astounding collection of papers containing deeds, pamphlets, maps, letters, and diaries and became the crown jewel of the Library. Reflections of the community's history are found in the Library Board's Minutes: increased book checkouts during the Depression, a traveling library for servicemen created in 1943, and most recently the posting of a "restaurant-type sign" that entry without shoes is prohibited.

The nieces and nephew of Charles W. Osborne gave property on the corner of Buell Lane and Main Street. Their gift was intended to serve a triple purpose: to enhance the beauty of Main Street, to ensure room for expansion of the beautiful East Hampton Library, and to pay tribute to the memory of their uncle.

The Long Island Collection continued to grow. It had by now become a trove of remarkable artifacts and documents: The 1641 deed to Shelter Island, a sash from the Huron Tribe given to Rev. Samuel Buell, a fragment of the cloth woven with gold thread that Captain Kidd gave to Mrs. Gardiner during his famous visit to Gardiner's Island in 1699, the East Hampton Book of Laws published in 1665, an Indian Bible of 1685, and first-hand reports of whaling voyages, witch trials, genealogical information, account books, diaries and deeds. 

A great library collection needs focus to be brilliant and the Long Island Collection more than meets that prerequisite. No other small town in America has such a collection of rare materials tracing the region's history back to its origins. To house it, the Gertrude Mumford Room, adjacent to the Gardiner Room, was built in 1946, with funds raised by subscription.

In 1948 the Thomas Moran Biographical Art Collection, which contained numerous drawings, etchings, personal memorabilia and biographical material, was donated to the library by the artist's daughter, Ruth. Thomas Moran and his family took part in every facet of village life for over seventy years, from 1878 to Ruth's death in 1948.

The year 1953 saw the addition of the Hedges room, named for Dayton Hedges who commissioned Jeannette Edwards Rattray to write "East Hampton History." The income generated from its sale helped pay to build the room.

In 1963 the long desired Children's Room was added in memory of Dorothy T. Quick. Story Hour and the popular summer reading programs were initiated.
 
In 1968 the Wallace Chaunceys renovated the attic to serve as a non-fiction stack. It has recently served as a staff work area. It was named the Aymar Embury Room in honor of the Library's architect. Embury also designed Guild Hall Museum directly across the street. These handsome landmarks are cornerstones of the Village's Historic District.

In 1976 the new Jeannette Edwards Rattray wing was dedicated. It honored a descendant of one of East Hampton's founding families, who was a gifted chronicler of the town's rich history. In that same year the Agnes Day Room was added.

In 1997, the Library's Centennial Year, an expansion and renovation designed by the noted architect Robert A.M. Stern was completed. Mr. Stern's plan not only restored the architectural integrity of the original design but also houses an extraordinary modern library and research facility. Computer-equipped study carrels, CD-ROM's, on-line catalogs, instant Internet access with email facilities are available. The new addition named in honor of John M. Olin, a long-time summer resident, doubled the size of the Library.

Libraries are the custodians of memory and the guardians of civilization. They have three functions: to acquire, to store and preserve, and to make material public. The East Hampton Library has admirably fulfilled these functions for the last century and will continue to do so for the next.

Jacqueline Quillen, "History of East Hampton Library" - 1997
Great-grandniece of Mary Stimson, Founder, East Hampton Library, 1897