I was deeply saddened to learn that Sir Terry Pratchett has died. The world has lost one of its brightest, sharpest minds, in over 70 books, Sir Terry Pratchett enriched the planet like few before Sir Terry Pratchett. As all who read Sir Terry Pratchett know,' Discworld' was Sir Terry Pratchett vehicle to satirize this world : Sir Terry Pratchett did so brilliantly, with great skill, enormous humor and constant invention.