<DIV>Among the most important and influential philosophical works in Western thought: <I>Euthyphro,</I> exploring the concepts and aims of piety and religion; <I>Apology,</I> a defense of the integrity of Socrates' teachings; <I>Crito,</I> exploring Socrates' refusal to flee his death sentence; and <I>Phaedo,</I> in which Socrates embraces death and discusses the immortality of the soul.</DIV>