The first time I saw Essays and Proofs from the archives of Bradbury Wilkinson, I thought they were magical. So clear, so crisp... and so interesting. I love stamps. I love the essays and proofs even more.
This website is devoted to creating a census of philatelic essays. I've started with United States, 1861 - 1870 because that's the area I collect. But I would welcome comments and contributions from others.