This Article explores the relationship between the First Amendment and criminal procedure. These two domains of constitutional law have long existed as separate worlds, rarely interacting with each other despite the fact that many instances of government information gathering can implicate First Amendment freedoms of speech, association, and religion. The Fourth and Fifth Amendments used to provide considerable protection for First Amendment interests, as in the famous 1886 case Boyd v. United States, in which the Supreme Court held that the government was prohibited from seizing a person’s private papers. Over time, however, Fourth and Fifth Amendment protection has shifted, and countless searches and seizures involving people’s private papers, the books they read, the websites they surf, and the pen names they use when writing anonymously now fall completely outside the protection of constitutional criminal procedure. Professor Solove argues that the First Amendment should protect against government information gathering that implicates First Amendment interests. He contends that there are doctrinal, historical, and normative justifications for developing what he calls “First Amendment criminal procedure.” Solove sets forth an approach for determining when certain instances of government information gathering fall within the regulatory domain of the First Amendment and what level of protection the First Amendment should provide.