There is no such thing as an Atheist Bible.
There is no Atheist Manifesto. No other documentation requires beliefs for Atheists around the world. Atheism is not a belief system so it follows no given rules. Atheists are individuals and each of us has our own philosophy, ideology, convictions, and thoughts.
There are web pages that have created humorous versions of an “Atheist Bible,” but they are obviously tongue-in-cheek. Some of them are outrageously silly and others are ridiculously funny. Of course, one has to understand that humor, by its very nature, pokes fun at the expense of others. While they are funny, they are blatantly funny at the expense of religionists. What is the point though if you cannot laugh at yourself?
Someone the other day asked me what book I would call my “Bible.” Notice how everything has a “Bible” – such as the “computer user’s Bible”, “welder’s Bible,” or the “Bible of essay writing” – they always seem to be “how to” books. If you forced me to pick one book that would be my “Bible” (my “how to” book) then I would have to choose the complete works of Robert Green Ingersoll. Then again, maybe I might choose Bertrand Russell. Of course, there is always George Smith, Charles Darwin, Carl Sagan, Massimo Pigliucci, Dan Barker, and Richard Dawkins.