In this accessible text complete with portraits, summary boxes and precise definitions of key terms, Johnston describes the mental workings of 18 of the greats. Working chronologically and also through themes, Johnston describes the trends from Socrates and Plato to Aristotle, Epicurus and Zeno, Aquinus, Descartes, Locke and Montesquieu, Spinoza, Hume, Kant, Marx, Nietzsche, Wittgenstein, Heidegger, Sartre and Derrida, opening each chapter with the most basic ideas and building to crisp explanations of some of the most complex ideas to ever hit paper. Although this can be read cover to cover to give high school students and the general public a running start, Johnston's appraisals and summaries also serve as references and refreshers.