Explore the wonderful, wild, and often weird world of esoteric programming languages. Beginning with the history and theory of programming languages, addressing concepts like Turing machines and Turing completeness. Then a tour of three 'atypical' programming languages, real languages that are unusual and require out of the box thinking. Then, five chapters on existing esoteric languages (esolangs). Finally, the remaining chapters detail the development and use of two entirely new programming languages.