Abstract This chapter provides a brief introduction to the scholarly conversation concerning burdens of persuasion. An adequate account of burdens must first explain what case-related facts the burden draws upon to produce outcomes. I review a variety of answers to this question, including probability threshold, likelihood ratio, belief function, weight-of-evidence, explanatory, and story-based approaches. I then identify several key questions that theories must answer with respect to inputs and show that the best answer on any given question must depend on whether the theory is advanced as a psychological, doctrinal, or normative account. The remainder of the chapter considers varying methods of transforming these inputs into case outcomes, including fixed thresholds, variable thresholds, multi-stepped, and continuous approaches. With respect to these choices, the problem of describing current practices is much easier, but the normative debates are harder to resolve.