Dear All, You are warmly welcomed to the 83rd Peripatetic Seminar on Sheaves and Logic, to be held in Glasgow, Scotland, on 6-7 May. Our invited speaker is Jon Woolf, who will give us an introduction to derived categories. To register, request accommodation, and find out more, visit http://www.maths.gla.ac.uk/~tl/pssl/ Best wishes, Tom Leinster Richard Steiner