Scent is the "bacterial, cellular and vaporous debris enshrouding the individual." The debris becomes deposited in the environment in a conically shaped pattern known as the scent trail. The uniqueness of human scent permits law enforcement to use scent evidence to follow a suspect from a crime scene, identify a suspect in a lineup, and locate and recover missing persons, whether dead or alive. Law enforcement agencies cannot rely on scent evidence alone to accomplish these tasks; they must use specially trained dogs to link the evidence to the individual and the crime. The article describes working with scent-discriminating dogs, preserving the crime scene, collecting scent evidence and presenting scent evidence in court. Because the scent of every human being is nearly as unique as a fingerprint, scent evidence can help investigators find missing persons, uncover evidence, and locate suspects and link them to specific crimes. Notes