David Eppstein, a regular contributor to Wikipedia, asked me recently about background relevant to his recent work on the Birkhoff duality of finite posets and finite distributive lattices. This resulted in several exchanges that can be seen at http://en.wikipedia.org/wiki/User_talk:Vaughan_Pratt#Birkhoff.27s_representa... His last message requested citable references concerning my explanation of the duality. The best I could come up with was Peter Johnstone's *Stone Spaces*, which is where I learned about these particular dualities. However my answer to his earlier question was phrased in what I felt was more elementary language than used by Peter (but of course "elementary" is in the eye of the beholder). My question here is, where in the literature is there an account of Birkhoff/Stone duality in terms of homming into schizophrenic objects at a level comparable to my detailed reply to David? The concept itself can be presented at a very elementary level, but the expositions of it that I'm aware of presume a degree of sophistication of the reader out of proportion to what the concepts should require in this case. If Peter's book is indeed the most elementary account available I'll settle for that. Whatever's available. Vaughan