I love the title and subtitle, and that "Smart People" stands out... but the color block scheme on the whole reminds me of a text book, and I'm not sure if that's what you were going for. (You might be -- you did say the book was "hardcore and cerebral".)
I'm actually rather partial to the one that Tuumble designed on the white background, not just because of the general look, but because of the little bits of scripted font make me think of the Declaration of Independence and the tie in to the "pursuit" of personal growth to the pursuit of happiness. Perhaps I'm reading too much into it though.
