For those who need some context: In 1983 David Warren published a paper describing an abstract machine that could be used as the target of a Prolog compiler. This machine became the basis of most Prolog compilers - it is much faster than interpreters. His paper was not easy to understand. Hasan Air-Kaci's book was a brilliant exposition of Warren's work, and was a must-read for anyone serious about working on Prolog interpreters or compilers.
Note that this is Professor David HD Warren. As opposed to Professor David S Warren, who led the XSB Prolog team. Which is built around the Warren Abstract Machine.
Oh dear, that reminds me of one of my courses I had to take where we had to memorise the WAM and execute it on paper in the exam. Most useless course ever.
That's cruelty. Where did this happen?
Many years ago in Germany.