Louis Henry Sullivan (September 3, 1856 – April 14, 1924) was an American architect, and has been called the "father of skyscrapers" and "father of modernism". He is considered by many as the creator of the modern skyscraper, was an influential architect and critic of the Chicago School, was a mentor to Frank Lloyd Wright, and an inspiration to the Chicago group of architects who have come to be known as the Prairie School.
Along with Wright and Henry Hobson Richardson, Sullivan is one of "the recognized trinity of American architecture". The phrase "Form follows function" is attributed to him, although he credited the origin of the concept to an ancient architect whose origins were allegedly Italian. In 1944, Sullivan was the second architect to posthumously receive the AIA Gold Medal.
- Martin Ryerson Tomb, Graceland Cemetery, Chicago (1887).
- Auditorium Building, Chicago (1889).
- Carrie Eliza Getty Tomb, Graceland Cemetery, Chicago (1890).
- Wainwright Building, St. Louis (1890).
- Charlotte Dickson Wainwright Tomb, Bellefontaine Cemetery, St. Louis (1892), listed on the National Register of Historic Places is considered a major American architectural triumph, a model for ecclesiastical architecture, a "masterpiece", and has been called "the Taj Mahal of St. Louis." The family name appears nowhere on the tomb.
- Union Trust Building (now 705 Olive), St. Louis (1893; street-level ornament heavily altered in 1924).
- Guaranty Building (formerly Prudential Building), Buffalo (1894).