I remember using this language in the AI class, i thought it was an old, deprecated language as people now use python mainly, really cool to see it again
1. Make simple problems easy.
2. Make difficult problems possible.
Python is an outstanding language on both scores.
Prolog, alas, is much better at #2 than it is at #1. For example, prolog is a great choice for writing domain-specific languages, and modern implementations (like scryer prolog, mentioned in a comment above), can generate very efficient code for them.
Prolog's "killer ap" is how well it does on a third feature:
3. It makes virtually impossible tasks "merely" very difficult ;-)
And it has a steep learning curve; it took me years to really "get" it, and I only persevered because I was facing one of those category #3 problems.
Its not a deprecated language, but alas, it is destined to be a niche language. But for those niches, it is still the best, hands-down.
So I decided to try to implement the features I needed on top of the theorem prover which prolog already is.
Took me forever, but eventually it all came together like a thunderclap, and I was able to implement a theorem prover for quantified, higher-order modal logic which was amazingly-blazingly fast--in 67 lines of prolog.
In terms of lines-of-code per day, its the least productive I've ever been :-)