Frederick Dretske's views on the nature of seeing, the possibility of knowledge, the nature of content or non-natural meaning, the nature of behaviour, and the role of content in the causal explanation of behaviour have been profoundly important. "Dretske and his Critics" contains original discussions of these issues. In "Seeing and Knowing" Dretske argued that this is a relational sense of seeing according to which, if one sees X, then X exists (or occurs); and if one sees X,and X = Y, then one sees Y. He carefully contrasted seeing in this relational sense with seeing that something is the case. In his contribution to this volume, Heil examines Dretske's notion of non-epistemic seeing. Dretske is largely responsible for the relevant alternatives response to scepticism about knowledge. In arguing that we cannot know the sorts of things we ordinarily claim to know, the sceptic appeals to irrelevant alternatives that the purported knower cannot eliminate. Cohen and Sanford examine this response. In "Explaining Behaviour - Reasons in a World of Causes" Dretske defended a component account of behaviour, and offered original, naturalized accounts of the nature of content and of the role of content in the causal explanation of behaviour. In their contributions, Kim, Adams, Dennett, Cummins, and Horgan examine Dretske's account of behaviour and his naturalized account of the role of content in the causal explanation of behaviour. McLaughlin focuses on Dretske's naturalized account of content.