In the late 19th century, James W. Scoville helped establish a Pastor's Library room at First Congregational Church (now First United Church). The private subscription library moved into the newly constructed Scoville Institute at 834 Lake Street in 1888. In 1902 Oak Park voters approved a tax to fund a public library. In 1903 the library became public when citizens elected the first Library Board of Trustees.
More history of the Main Library. 
Maze Branch Library
In 1915 the Oak Park Public Library opened the South Branch Library in a rented building on Harrison Street. In 1936 the South Branch moved to a new facility at its present location at the corner of Gunderson Avenue and Harrison Street. The South Branch was re-named for librarian Adele H. Maze in 1957.
More history of the Maze Branch Library. 
Dole Branch Library
The North Branch Library was originally housed at Fair Oaks Pharmacy at Ridgeland and Chicago Avenues. In 1939 Mr. and Mrs. Andrew Dole presented the building at Augusta Street and Cuyler Street to the Village of Oak Park to be used for for "cultural and recreational purposes." In 1940 the North Branch Library moved to its current location in the re-modeled, village-owned Dole building and became the Dole Branch Library.
More history of the Dole Branch Library.