Book excerpt: This historically based collection of philosophers' reflections--the letters, journals and prefaces that reveals their hopes and hesitations, their triumphs and struggles, their deepest doubts and convictions--allows us to witness philosophical thought in process. Ranging from Plato to Hannah Arendt, with contributions from 44 philosophers (Augustine, Maimonides, AlGhazali, Descartes, Pascal, Leibniz, Voltaire, Rousseau, Hobbes, Hume, Kant, Nietzsche, Kierkegaard, Wittgenstein, among others) this remarkable collection documents philosophers' claim that they change as well as understand the world. In her introductory essay, "Witnessing Philosophers," Amelie Rorty locates philosophers' reflections in the larger context of the many facets of their other activities and commitments.