Warren's Abstract Machine: A Tutorial Reconstruction
that was published by MIT Press, in 1991 under ISBN 0-262-51058-8 (paper) and ISBN 0-262-01123-9 (cloth) is now out of print, MIT Press having decided against a new printing (apparently because of lack of demand). I now own the copyright and do not mind distributing it for free to anyone who wants to use it for non-commercial purposes.
If you retrieve it, all I ask is that you let me know who you are, and for what purpose you intend to use it.
Here is also a set of transparencies that I used for my lectures on the WAM at the International Conference on Logic Programming (1991, Paris, France). I claim sole copyrights of these, and request that you kindly inform me if you download them. Thanks.
PLEASE NOTE THAT THIS IS MADE PUBLIC "AS IS" AND THAT THE ERRATA APPLY TO THE BOOK AND SLIDES - EVEN THOUGH THE PAGE REFERENCES OF THE ERRATA POINT TO THE MIT PUBLICATION PAGE NUMBERS. (but it is easy to make the link to the reprinted version... you must do some work too!... and this is free after all...)