It’s worth noting that the letter from Foucault is only one page, with an introduction by Ange Pierraggi on the other side of the two-page spread. The Instagram picture and another of Foucault at Münsterlingen are on these pages.

On the visit Foucault, Jacqueline and Georges Verdeaux made to Münsterlingen in 1954, see the remarkable book Foucault à Münsterlingen, edited by Elisabetta Basso and Jean-François Bert (EHESS 2015).