Due to the problems with first-order logic mentioned in Chap. 4, pure logic can not solve most realistic AI problems. Logic programming as a fusion of logic and procedural programming provides the programmer with means for controlling and optimizing logical reasoning. Using the programming language PROLOG, we invite the reader to solve some simple relational problems and puzzles. As a particular highlight, we introduce constraint logic programming, which enables us to elegantly solve for example non-trivial scheduling problems.