Antitheism is active opposition to theistic belief. It is distinguished from simple atheism in that it is not simply a rejection of belief in God; rather, the antitheist is actively opposed to such belief.  While a particular atheist might be content to deny the existence of God, but leave others to their own faith, the antitheist will actively seek to undermine or eliminate the faith of others. Thus, all antitheists are atheists, but not all atheists are necessarily antitheists. Antitheism is also sometimes referred to as militant atheism, and is prominent amongst people who see religion as promoting hatred.
Historically, antitheism has been a hallmark of repressive totalitarian regimes. Belief in God is a threat to those who want to make the State the supreme authority; consequently, those who believe in God in such a society are persecuted. Stalinist Russia was an example of such a regime.
Today, antitheists are quite visible; a number of high-profile antitheists spread their message through books and lecture tours. Well-known antitheist authors include Christopher Hitchens and Richard Dawkins, both of whom have made substantial sums of money by attacking religion and faith.
Antitheists are also active in the political arena. One such well-known antitheist political activist is Michael Newdow, an attorney who has repeatedly sought to eliminate any mention of God from the public arena.