This is to advertise my article: Three themes in the work of Charles Ehresmann: local-to-global; groupoids; higher dimensions. available on arXiv:math.DG/0602499 and to appear in the Proceedings of the 7th Conference on the Geometry and Topology of Manifolds: The Mathematical Legacy of Charles Ehresmann, Bedlewo 8.05.2005-15.05.2005 (Poland) Banach Centre Publications. There is a discussion on http://www.math.columbia.edu/~woit/wordpress/?p=352 Ronnie Brown www.bangor.ac.uk/r.brown