Through the rearview mirror of five state antitrust challenges, this Article provides a tour of state antitrust enforcement—from small cases brought by single states that made a splash, to cases so pivotal to antitrust practice that it seems as if there is nothing left unknown about them. The author discusses state challenges in Microsoft, Ovcon, Namenda, T-Mobile/Sprint, and Vyera, and provides a behind-the-scenes look at the impacts that these cases had on state enforcement. This Article also provides insights into how these cases affect current state antitrust litigation, and what observers might expect from the road ahead. [ABSTRACT FROM AUTHOR]