Not exhaustive, but a great quick A-to-Z reference of quotes by atheists, freethinkers and philosophers--almost a greatest hits, if you will. Some quotes are very anti-theist in nature while others lean more political or non-religious. There are even a few appalling quotes by the religious.
Coming from a religious background, the editor put these quotes together based on what helped him leave religion behind. Citing Atheists is a great book to add to any skeptic's library without the heavy cost of a huge, exhaustive volume.
Authored by Steve Dustcircle, Christopher Hitchens, Richard Dawkins, Sam Harris, Thomas Paine, Mark Twain, Robert Ingersoll, Paul Kurtz, Carl Sagan, Benedict Spinoza, Gore Vidal, James Madison, Richard Leakey, H. L. Mencken, Jack Kevorkian, Julia Gillard, Benjamin Franklin, Albert Einstein, John Adams, Pat Condell, Mikhail Bakunin, and more.