Who is Philosophers from Sophie's World and what is their importance?

Numerous philosophers are discussed throughout the text. These philosophers include Thales, Socrates, Plato, Aristotle, Cicero, Augustine, Thomas Aquinas, Pico della Mirandola, Hobbes, Locke, Hume, Kant, Kierkegaard, Berkeley, Marx, Darwin, Freud, Sartre and others.