Practical Foundations of Mathematics, ISBN 0-521-63107-6 To be published by Cambridge University Press, as number 59 in their series Cambridge Studies in Advanced Mathematics (which includes books by Peter Johnstone and by Jim Lambek and Phil Scott). Please see http://www.dcs.qmw.ac.uk/~pt/book/index.html for details. This is the LAST CALL FOR COMMENTS. The text is already in the hands of the copy editor for the second time. CUP hopes to have it published in time for the International Congress of Mathematicians in Berlin in August, which means I have to finish it by the end of May. I am aware that my policy of only giving away single chapters has annoyed people a bit, but it has been successful in its objective of getting attention for the whole book. (The most assiduous reader of "Proofs and Types" got to chapter 12 out of 15). I don't intend to distribute any more chapters now, though if I owe you a copy of the whole draft because you sent me comments on a chapter, please ask (tearing apart sections 1.1 and 1.2 does not count). If you have a copy of part of the book and have noticed a mis-conception, please SPEAK NOW OR FOREVER HOLD YOUR PEACE. There is really no point in telling me about missing commas in any but the most recent versions (ie 1998) as other readers, the copy editor and I have been through the text several times since I last distributed copies (in July 1997). When I am rid of the book itself, I intend to set up a web site as a repository for citations, discussion, answers to exercises and, inevitably, corrections. With the permission of the people concerned, I intend to publish some of the correspondence I have had about the book in this way, and there will be automatic facilities for readers to add further comments. Therefore any comments you have about the book which are too late for publication or which are not suitable for inclusion will not be wasted. I would like thank Pierre Ageron, Lars Birkedal, Luca Cattani, Michel Chaudron, Thierry Coquand, Robert Dawson, Luis Dominguez, Peter Dybjer, Susan Eisenbach, Fabio Gadducci, Gillian Hill, Martin Hyland, Samin Ishtiaq, Achim Jung, Stefan Kahrs, J\"urgen Koslowski, Steve Lack, Jim Lambek, Charles Matthews, Paddy Mccrudden, James Molony, Edmund Robinson, Pino Rosolini, Martin Sadler, Alan Sexton, Thomas Streicher, Charles Wells, Graham White, Andrew Wilson and Todd Wilson for taking the trouble to read parts of the draft and giving their detailed comments on it. (Please tell me if you think you should be on this list but aren't.) Paul Taylor