An incredibly profound book that starts out to defend the open society as we know it (see OthernessMeme). In order to do that, Popper debunks the great philosophers that have tried to teach the opposite, starting with Plato. Plato argued in TheRepublic for a PhilosopherKing, wise, benign, well educated, controlling a city state controlled by a warrior caste. No plays and no fooling around to corrupt the feeble minded. This, Popper says, cannot be anybody's wish. Life would be miserable. And there is no improvement possible, as all but the king's closest live in humble sheep-like stupidity.
Next are Heidegger and Hegel. Both were magicians with words, wordy magicians, profound, deep. By constant redefinition of words, texts emerged that no sane person could understand. For an example, see Hegel's Encyclopedia of the Philosophical Sciences in Outline, ISBN 0826403409 (alternate, search). (Sadly, Schopenhauer who taught at the same university as Hegel, had much less success.) Anyway, Heidegger and Hegel are debunked by Popper.
Hegel was also a defender of historicity, the theory that society advances through stages, finally reaching some state of perfection. This theory is debunked as well, including Karl Marx and his idea of society advancing through stages from capitalism through socialism to communism.
In the last part of the book, Popper examines the problems and the solutions available:
What emerges is the Open Society.
Where Dewey and Popper diverge, in the view of Richard Rorty (one of Dewey's modern-day descendants), is in Popper's attempt to draw a sharp distinction "between fact and value, and between science on the one hand, and ideology, metaphysics and religion on the other. These were distinctions which both [William] James and Dewey did their best to blur." --LynHeadley
I haven't read this book, but the criticism of TheRepublic sounds like a straw man to me. Plato did advocate for an oligarchy, but the main point I got was that politics should be governed by logic and reason. Plato was certainly not an advocate of blindly following authority. Popper's view of Plato was probably too distorted by the rise of fascism. -- JoeHendrix?