Get the first edition for $3.82:

http://www.amazon.com/gp/offer-listing/0262192500/ref=tmm_hr...

...I got mine for like $2, and I've been very happy with it.

I haven't read "The Art of Prolog". But if you want to write correct and fast Prolog, reading "The Craft of Prolog" by Richard O'Keefe is a must.

It is quite good, and the hardcover version is beautiful as well -- good enough to be a coffee table book. But yeah, $250 is pretty steep.

You should be able to get it cheaper than that—I did. AbeBooks shows it available for $40 or so, plus p&p.

Hit up your local college library. Mine has a copy of it and it has been there every time I've gone by to check it out.