William Twining is the Quain Professor of Jurisprudence Emeritus at University College London and a regular Visiting Professor at the University of Miami School of Law. He was a pupil of Karl Llewellyn in 1957 8 and put Llewellyn's very extensive papers in order after his death in 1962. Twining's recent writings include Rethinking Evidence, 2nd edition (2006), General Jurisprudence (2009) and How to Do Things with Rules, 5th edition (with David Miers, 2010), all published by Cambridge University Press and recognizable as part of the realist tradition.