Though the “exclusionary rule” refers to a rule that emerged from Mapp v. Ohio, virtually all rules of evidence are exclusionary rules. The idea is to ferret out prior to admission potential evidence that is unreliable, impertinent, or not logically probative of a material issue. In the adversary system in the United States, the search for truth may be tortuous, but if the truth is to be known, some proffered evidence must be excluded. Among rules excluding such evidence, and foremost among those widely misunderstood, is the hearsay rule. Through discussion of three categories of apparent hearsay evidence and development of a comprehensive decision tree for evidentiary admissibility, this article is designed to dispel hearsay rule confusion.