Wilfrid Sellars was one of the most important philosophers of mind in the 20th Century. I just discovered that the complete collection of his unpublished papers and correspondence is available at the Archive of Scientific Philosophy at the University of Pittsburgh. The collection was created by Pitt archivist Lance Lugar, who also told me it’s now available. The finding aid is hard to find, but it’s there. The Archive also has many other important collections, including those of Carnap, Reichenbach, Ramsey, and Hempel.