Mastering Criminal Procedure: The Investigative Stage provides a concise treatment of the relevant federal constitutional doctrines that guide and constrain interactions between the police and individuals in the investigation of criminal conduct. The book provides an overview of the criminal process and the constitutional sources of the criminal procedure rules, including different approaches to constitutional interpretation. The focus is on the Fourth, Fifth, and Sixth Amendments as they relate to the warrant requirement for searches, exceptions that allow warrantless searches, the seizure of evidence and individuals, and the interrogation of suspects. The book covers the primary topics that arise in the typical law school criminal procedure course, including when the warrant requirement applies, the process for obtaining a valid warrant, the operation of the exclusionary rule, the range of exceptions to the warrant requirement, and arrests and other seizures of individuals and resultant searches of the person.