Brain Snacks: Tasty Tidbits of Knowledge
Ayn Rand was a staunch anti-communist, largely because of her bad experiences in Soviet Russia. She actually testified as a "friendly witness" at the rather infamous McCarthy Hearings, which started out as an effort to find communist spies in the government and turned into a congressional-led witch-hunt (Source).
The Fountainhead had a bit of a slow burn on its way to hit. It took it two years before it debuted on the New York Times bestseller list in August of 1945 (just as World War II was ending, incidentally). (Ayn Rand Institute Timeline)
Frank Lloyd Wright provided Rand with a lot of inspiration for the character of Roark and some of the buildings he designed in the novel. For example, Roark's design for Wynand's house bears a strong resemblance to Wright's Fallingwater (Source).