knobunc's reply is good. Check Language::Prolog As far as I know, it is currently a beta version.
But, if you want to "reinvent the wheel", you should consider reading something on the following topics:

• Propositional logic
• Predicate logic
• Herbrand's Theory
• Godel-Herbrand-Skolen Theorem
• Resolution and Robinson's Algorithm
• Horn Clause Programs
• Prolog

You can check them in that order :)
Logic programming slogan "I tell you what I know and what I'd like to know, without telling you how" showed its practical unapplicability over the years: every logic programming language includes extralogic operators, such as cut, that introduce elements of imperative programming in the language ("I tell you what I know and what I'd like to know, without telling you how... Well, I will help you a bit").
Despite of their impure nature, logic programming languages are very interesting and I think they're worth studying.