One chapter talks about the effects of zero/low gravity on the human body. The NASA doctors are still doing studies about this topic and pay people up to $17,000 for 3 months work. Since the work requires lying in bed, my first thought was, "i'd get so much reading done if i could get in on a study!". heh.
Roach has a winning writing style, very casual but informative. The footnotes are the best parts, DON"T skip them! a 6!