The Greatest Popular Science Book!

During the valuable discussions we had (and are still having) over on The Greatest Physics Paper! thread, a number of people mentioned books which work better in another category (at least in my humble opinion). So I think it is of value to start such a new discussion. Announcing Cosmic Variance's search for ...<drum roll>... The Greatest Popular Science Book! Furthermore, since a lot of the discussion on the other thread did get a bit technical, it might have frozen out several of the non-practicing physicists, or the people not trained in physics who nevertheless have an interest in science. In my view, a large part of the point of this blog is to interest you, and so major reader-participation driven posts should have something for you. So: Do talk about some of the non-textbook science books (e.g. popular expositions, biographies of a life and work, etc. and not neccessarily ...