Book excerpt: The guarantee of free speech enshrined in the U.S. Bill of Rights draws upon two millennia of Western thought about the value and necessity of free inquiry. Acclaimed legal scholar George Anastaplo traces the philosophical development of the idea of free inquiry from Plato's Apology to Socrates to John Milton's Areopagitica. He describes how these seminal texts and others by such diverse thinkers as St. Paul, Thomas More, and John Stuart Mill influenced the formation and the earliest applications of the First Amendment. Anastaplo also focuses on the critical free speech implications of a dozen Supreme Court cases and shows how First Amendment interpretations have evolved in response to modern events. Reflections on Freedom of Speech and the First Amendment grounds its vision of America's most basic freedoms in the intellectual traditions of Western political philosophy, providing crucial insight into the legal challenges of the future through the lens of the past.