The Cook Memorial Library, also known as the Ansel B. Cook House, is a historic house museum in Libertyville, Illinois, United States. It was built as a Victorian house for contractor and politician Ansel B. Cook in 1878. In his will Cook donated the home to be used as a public library, although it remained for many years the residence of Cook's longer-lived widow. After Emily Barrows Cook's death, the building received a major Neoclassical renovation that converted it into a library, opening to the public in 1921.