This professor is indescribably awesome.
HN Discussion: http://news.ycombinator.com/item?id=2039117
Take down request: http://www.cl.cam.ac.uk/~rja14/Papers/20101221110342233.pdf (pdf)
Professor Anderson's reply: http://www.cl.cam.ac.uk/~rja14/Papers/ukca.pdf (pdf)
It is available for free download from his own directory at CMU: http://www.cs.cmu.edu/~dst/LispBook/