Objectivism is the philosophy dreamed up by Russian-American immigrant Ayn Rand, who decided that she didn't want to stay in the Soviet Union after her family's business and home had been looted by the new government, which is based on the tenet that the world is real. One would think that that was self-evident but apparently that idea has been falling out of favor ever since some fellow called Kant came along and said we're living a noumenal world and Ayn Rand was just a noumenal girl.
Most people today are unfamiliar with this tenet of Objectivism (reality is real) and are more familiar with the political branch of the philosophy which holds that a reason based philosophy dictates that a person has a moral right to whatever he or she produces - which people usually call "being a greedy bastard" - but which Objectivists usually refer to as rational self-interest.
Ayn Rand made her philosophy known via the novel Atlas Shrugged which received glowing reviews from the left and right of the political spectrum when it was released; Gore Vidal proclaiming it to be "nearly perfect in its immorality" and Whittaker Chambers of the National Review allegedly hearing "to a gas chamber – go!" as he read it (probably one of his old Soviet spy radios he forgot to turn off), and which to this day does not cause anybodies knickers to twist around in their pants the moment you mention it. Other works of fiction include The Fountainhead (blowing up buildings is fun) and We The Living (communism is not).
Alongside those novels she laid out the various tenets of her philosophy in such nonfiction works as The Virtue Of Selfishness (being allowed to keep your wage slip is cool) and The Romantic Manifesto (old fashioned art is so sexxay), Introduction to Objectivist Epistemology (and so are long words) and many lectures she gave in the Ford Hall Forum. 
Ayn Rand Institute website.