This is not your typical class in computer science, or in formal logic; but you will learn a lot about both by taking it. Our subject will be one of the most important and influential papers that has ever been written—“On Computable Numbers, with an Application to the Entscheidungsproblem,” by Alan Turing. This is the paper that birthed computer science as a discipline. Understanding it requires that you be comfortable with some mathematical concepts (powers and roots) and with thinking abstractly; but the most important prerequisite for understanding this paper is determination. What is the best way to characterize Turing’s paper? Simple. It changed the world.