mounted on my wheelchair by David Mason. This system has made all the difference: In fact | can communicate better now than before I lost my voice. have had suggestions of how to improve the book from a large number of people who have scen preliminary versions. In particular, Peter Guzzardi, my editor at Bantam Books, sent me pages and pages of comments and queries about points he felt that I had not explained properly. 1 must admit that | was rather irritated when I received his great list of things to be changed, but the was quite right 'm sure that itis a better book as a result of is ‘Thomas, and Raymond Laflamme; my secretaries Judy Fella, Ann Ralph, Chery! Billington, and Sue Masey; and my team of nurses. None of this would have been possible without the support for my research and medical expenses that has been supplied by Gonville and Caius College, the Science and Engineering Research Council, and by the Leverhulme, McArthur, Nuffield, and Ralph Smith Foundations. I'm very grateful to them. Hawking 20th October 1987