The Fountainhead is a 1943 novel by Ayn Rand. It was Rand's first major literary success and brought her fame and financial success. More than 6.5 million copies of the book have been sold worldwide.

The Fountainhead's protagonist, Howard Roark, is an individualistic young architect who chooses to struggle in obscurity rather than compromise his artistic and personal vision. The book follows his battle to practice what the public sees as modern architecture, which he believes to be superior, despite an establishment centered on tradition-worship. How others in the novel relate to Roark demonstrates Rand's various archetypes of human character, all of which are variants between Roark, the author's ideal man of independent-mindedness and integrity, and what she described as the "second-handers." The complex relationships between Roark and the various kinds of individuals who assist or hinder his progress, or both, allow the novel to be at once a romantic drama and a philosophical work. Roark is Rand's embodiment of the human spirit, and his struggle represents the triumph of individualism over collectivism.

The manuscript was rejected by twelve publishers before a young editor, Archibald Ogden, at the Bobbs-Merrill Company risked his job to get it published. Despite mixed reviews from the contemporary media, the book gained a following by word of mouth and became a bestseller. The novel was made into a Hollywood film in 1949. Rand wrote the screenplay, and Gary Cooper played Roark.