This document provides an introduction to Ajahn Sumedho's teachings on the Four Noble Truths. It discusses the Buddha's first sermon given in the Deer Park at Varanasi, in which he taught the Four Noble Truths. Each of the Four Noble Truths contains three aspects, for a total of twelve insights. Ajahn Sumedho uses the Four Noble Truths as a framework for investigating suffering and non-suffering in daily life. Though considered basic teachings, Ajahn Sumedho finds the Four Noble Truths to be profoundly insightful for reflection throughout one's entire practice.