About a week before he died, I wrote to Tom Main, letting him know how important this paper, ‘Knowledge, Learning and Freedom from Thought’, had been for me. I am pleased to be involved in its publication here so that it can reach a wider readership. Apparently it was written on a plane during an attack of dysentery and Main thought it not well written, a view I do not share! I first came across the paper nearly three years ago, shortly after my arrival at the Cassel, when it was presented at a journal club by a senior registrar (Toby Thompson, to whom I remain indebted). Since then I have found myself referring to it in various different contexts. It is a paper of relevance not only to work in institutions but to psychoanalysis in general. It also raises some very important issues concerning the training of psychoanalysts, which I will return to later.