Not good. I bought this book for a buck hoping to get some scientific insight into spirulina, but there's only a few studies amid lots and lots of hype. This is to be expected since this book was written a long time ago when the studies were first coming out. But all this means is that it should have focused on more anthropological rather than strictly scientific stuff. I mean, we're asked to believe that grown men signed affidavits claiming to live upon nothing but 3 tablespoons of spirulina per day for a month at a time and even felt great while doing so. This is not a calorie-rich food and such an imbalance could therefore kill you. Too bad, since spirulina is a wonderful product and deserves more scientific research presented in an austere kind of way.