What is knowledge by acquaintance?

Russell famously posited a type of knowledge distinct from and irreducible to propositional knowledge, which he called knowledge by acquaintance. In recent years, several epistemologists have reignited interest in knowledge by acquaintance, pointing out an array of theoretical jobs it is serviceable in performing. Nonetheless knowledge by acquaintance continues to be met with resistance and disregard. I surmise that this has partly to do with the specific conception of knowledge by acquaintance propounded by Russell and many of his followers - what I will call here the "classical conception" of knowledge by acquaintance. At the heart of this conception are two theses, which I will label relationalism and infallibilism and try to articulate more fully in what follows. The main aim of this paper, however, is to construct an alternative notion of knowledge by acquaintance - fallibilist and non-relationalist - and argue that this alternative conception is just as fit to perform the theoretical jobs identified by proponents of knowledge by acquaintance. The hope is to thereby rescue knowledge by acquaintance from its relationalist and infallibilist associations, the better to foster its wider acceptance.