One of the central protections of our system of criminal justice is the right of the accused in all criminal prosecutions to be confronted with the witnesses against him. It provides assurance that prosecution witnesses will give their testimony in the way demanded for centuries by Anglo-American courts-in the presence of the accused, subject to cross-examination- rather than in any other way. Witnesses may not, for example, testify by speaking privately to governmental agents in a police station or in their living rooms. Since shortly after it was adopted, however, the confrontation right became obscured by the ascendance of a broader, but much weaker doctrine, the rule against hearsay. That rule is not limited to testimony-it applies to...