This book is the User Manual for CSP-Rules-V2.1, a generic pattern-based (or rule-based) solver of finite binary Constraint Satisfaction Problems (CSPs). The associated software, CSP-Rules-V2.1, is available on GitHub. It includes fully developed applications to logic puzzles such as Latin Squares, Sudoku, Futoshiki, Kakuro, Map Colouring, Numbrix, Hidato and Slithering. This third edition includes additions related to reducing the number of steps in a resolution path and to a newly discovered pattern (tridagon) for extremely hard puzzles.