In this paper, I consider the question of what it is to assert at all. I discuss and reject some competing answers to this question, e.g., a simple syntactic view of assertion, and a knowledge-based view of assertion. But I argue that the right view of assertion does need to make use of some epistemic notions. I go on to offer and defend my own answer to the central question. I argue that my view gets the right results in a range of cases, and also, that it provides the basis for an attractive answer to a related question, namely, how we come to know things via the testimony of others.