Although the development of high-technology investigatory devices has increased the debate over the reach of the Fourth Amendment, the inherent tension between technology and the Fourth Amendment is not new. Pursuant to the language of the Fourth Amendment, law enforcement practices are not required to be “reasonable” unless they are either “searches” or “seizures.” Therefore, central to an understanding of the Fourth Amendment is the perception of what police activities, under what circumstances, and infringing upon what areas and interests, constitute either a search or a seizure within the meaning of that Amendment. Historically, there has been debate on whether technology enhanced investigatory devices constitutes a Fourth Amendment “search” requiring a warrant. Because early Fourth Amendment jurisprudence revolved around the protection of property rights, the Court’s early rulings found that a “search” occurred only when law enforcement authorities physically trespassed into certain “constitutionally protected areas.” For example, in the 1927 decision in United States v Lee, the Court held that the Coast Guard’s mere use of a searchlight to illuminate the deck of a ship carrying illicit liquor was not a “search” within the meaning of the Fourth Amendment. The Court’s property-based notions of the Fourth Amendment survived until its 1967 decision in Katz v United States. The Katz decision raised more questions than it answered, causing the court to return again and again to the questions of what constitutes a search. The Court’s ruling in Kyllo v United States stands for the important proposition that the use of technological devices by law enforcement authorities to explore details inside a home that would previously have been unknowable without a physical intrusion constitutes a “search” within the meaning of the Fourth Amendment. Such a search is presumably unreasonable if it is conducted without a prior showing of probable cause and the obtaining of a search warrant. But the decision of Kyllo is vague concerning whether technological searches in public areas, such as Tampa’s digital facial recognition system, are legal. This article also considers the important practical issues for counsel on matters relating to this developing area of law.