The Buddha famously said, "I teach dukkha [suffering or reactivity or a sense of unsatisfactoriness] and the cessation of dukkha.” We explore this core teaching as it is expressed in the Four Noble Truths and the teachings of the Two Arrows and Dependent Origination, including ways that it can be confusing. We suggest ways to understand and implement this teaching both in formal meditation and in everyday life. (See document 328 below, on "Four Meanings of Dukkha, and Contact to Grasping in the Dependent Origination Model.")