It's common and not unreasonable to give an introduction to topos theory by starting from motivations in various subjects including algebraic topology and geometry. MacLane and Moerdijk explain these motivations in some detail, and of course the original papers on toposes presupposed knowledge of algebraic geometry. But I feel that I understand toposes better than the motivating subjects. Does anyone know of any good "extraductions from" topos theory that use topos intuitions to help introduce the concepts and methods of algebraic topology and algebraic geometry? Steve Vickers. ==============================================================================