1962 Air conditioning is installed. With the population of the Three Village area approaching 8,000 and the Library's collection reaching 15,000 books, the decision is made to expand. A two-story addition, comprising the present circulation desk area and downstairs community room, is completed and opens to the public. With the Library's book collection surpassing 90,000 volumes and the local population nearing 40,000, Three Village voters approve a second expansion project. After a year and a half of construction the Library celebrates the completed expansion with a grand reopening on January 24.
New space includes the present children's room, adult reference area and book stacks, and mezzanine.
The Library's holdings and borrower records are entered into a computer database for the first time, allowing for quicker and more efficient circulation. An automated replacement for the card catalog will follow eight years later. The library completes a new building expansion project. The expansion includes a new Children's Library, expanded Adult Services and increased parking. The Emma S. Clark Memorial Library is Suffolk County's oldest public library in terms of continuous community service from its original location.