In this journal article, the author examines the common “knock and announce” procedure used by law enforcement officials, in order to examine the various ways in which this procedure is interpreted. Following a discussion of the ways in which law enforcement officials must knock and announce their presence when serving a warrant in order to adhere to the Fourth Amendment to the Constitution, the author reviews United States Supreme Court cases challenging the way that “knock and announce” is interpreted. While Ker vs. California was the first court case to address the “knock and announce” requirement, it was not until Wilson vs. Arkansas that the Supreme Court was able to address whether the common-law “knock and announce” principle formed a part of the Fourth Amendment reasonableness inquiry. Following a discussion of Wilson vs. Arkansas maintaining that “knock and announce” was deemed reasonable under the Fourth Amendment, this article presents details of subsequent Supreme Court decisions and Lower Court decisions that have sought to identify what is considered “unreasonable” under the Fourth Amendment. The author concludes that the Supreme Court acted justly in their decision in Wilson vs. Arkansas. References