From the museum's website: http://www.dupageco.org/museum/generic.cfm?doc_id=2429

"The Museum building dates to 1891, when it opened as the Adams Memorial Library. Privately built by John Quincy Adams (a distant relative of the Adams presidents), he established the library in memory of his wife, Marilla Phipps Adams, who died in 1874.

"John Quincy Adams selected architect Charles Sumner Frost to design the Adams Memorial Library. Though only in his 30s, Frost had already designed a variety of private residences, public buildings, and commercial structures, including collaborating on Mr. and Mrs. Potter Palmer’s mansion on Chicago’s Lake Shore Drive.

Frost designed 127 different properties for the Chicago & NorthWestern Railroad, including depots for Wheaton and Wayne in 1887, his home state of Maine’s building at the 1893 World’s Columbian Exposition, and in 1916, Municipal Pier in Chicago, now known as Navy Pier."

"Frost designed the Adams Memorial Library building in the Richardsonian Romanesque style. Henry Hobson Richardson, a Boston architect, was the first American architect to give his name to an architectural style. Many architects used the style, or interpretations of it, and it became a favorite for important civic, religious, and commercial structures. Always of masonry, the style is marked by rough-faced, squared stonework, often in contrasting colors. Other details include wide rounded arches, towers, broad hipped roofs with cross gables, and areas of carved ornamentation.