What is computation? This is the question that birthed Computer Science as a discipline, and serves as the focal point of this course. Our plan for answering it is twofold. First, we will introduce functional programming through Scheme (a dialect of Lisp). Second, we will use our understanding of functional programming to explore the nature of computation itself. This will involve reading parts of Alonzo Church’s revolutionary article, “An Unsolvable Problem of Elementary Number Theory.” We will see how the notion of computation emerges from his understanding of functions, and engage with the fundamental conjecture of Computer Science (the Church-Turing Thesis).