The Supreme Court's 1919 decision in Schenck vs. the United States is one of the most important free speech cases in American history. Written by Oliver Wendell Holmes, it is most famous for saying that 'shouting fire in a crowded theater' is not protected by the First Amendment. The case itself upheld an espionage conviction, but it also created a much stricter standard for governmental suppression of speech. Over time, the standard Holmes devised made freedom of speech in America a reality rather than merely an ideal. In The Free Speech Century, two of American's leading First Amendment scholars, Geoffrey Stone and Lee Bollinger, have gathered a group of the nation's leading legal scholars (Cass Sunstein, Lawrence Lessig, Laurence Tribe, Kathleen Sullivan, Catherine McKinnon, and others) to evaluate the development of free speech doctrine since Schenk and assess where it might be headed in our post-Snowden era. Since 1919, First Amendment jurisprudence in America has been a signal development in the history of constitutional democracies?remarkable for its level of doctrinal refinement, remarkable for its lateness in coming (in relation to the adoption of the First Amendment), and remarkable for the scope of protection for free expression it has afforded since the 1960s. Since 1919, the degree of judicial engagement with these fundamental rights has grown exponentially. We now have an elaborate set of free speech laws and norms, but as Stone and Bollinger stress, the context is always shifting. New societal threats like terrorism, heightened political sensitivities, and new technologies of communication continually reshape our understanding of what sort of speech should be allowed. Publishing on the one hundredth anniversary of the decision that established free speech as we have come to understand it today, The Free Speech Century will serve as essential overview for anyone interested in how our understanding of the First Amendment transformed over time and why it continues to change to this day.