Wilfrid Sellars (1912–89) has been called the most profound and systematic epistemological thinker of the twentieth century. Many of his ideas have become widely acknowledged, including his attack on the "myth of the given", his functionalist treatment of intentional states, his proposal that psychological concepts are like theoretical concepts, and his suggestion that attributions of knowledge locate the knower "in the logical space of reasons". Sellars is, however, notoriously difficult to understand. His essays are complex and sometimes rely on doctrines and arguments he put forward elsewhere. Although each of his articles is deepened and strengthened by seeing it in its systematic context, Sellars never wrote a unified exposition of his system. Willem deVries addresses these difficulties and provides a careful reading and remarkable overview of Sellars's systematic philosophy. This clear, comprehensive and authoritative work will become the standard point of reference for all philosophers seeking to understand Sellars's hugely significant body of work.

"A hugely valuable gift to philosophy. It accurately and clearly summarizes the work of perhaps the most difficult major twentieth-century figure in philosophy, and in a way that makes his hugely important contributions accessible to all. It is far and away the most accurate and accessible commentary that we now have on Sellars."

Ruth Millikan