Also, for a non-general public but otherwise gentle technical introduction to toposes, here is a set of lectures with Andre Joyal. Presently, I am finishing up part 1 of 4 and would love to chat with any other interested parties. https://www.youtube.com/watch?v=Ro8KoFFdtS4 -- Sent from: http://friam.471366.n2.nabble.com/