Important Takeaways Architect Louis H. Sullivan developed the expression "form follows function" in his 1896 article "The Tall Office Building Artistically Considered." The term alludes to the concept that the outer architecture of a skyscraper should represent the many inside functions. For example, if there were a fire on the thirtieth floor, it would not be appropriate for that area to have the same decorative treatment as other floors. Sullivan also believed that buildings should be designed with human welfare in mind. He argued that tall office buildings could provide healthful work environments by allowing more natural light into the offices and by reducing noise levels. He also thought they might help prevent suicides by preventing feelings of depression among employees who felt isolated from their colleagues during periods of heavy construction. In conclusion, Louis Sullivan proved to be one of the first architects to put functionalism before aesthetics. His ideas helped bring about the modern office building era, which lasted until around 1960. Although some critics claim that this style of building has been used since then, the modern office building actually came into being in New York City in the early 20th century.