The μ-TBL system represents an attempt to use the search and database capabilities of the Prolog programming language to implement a generalized form of transformation-based learning. In the true spirit of logic-programming, the implementation is 'derived' from a declarative, logical interpretation of transformation rules. The μ-TBL system recognizes four kinds of rules, that can be used to implement various kinds of disambiguators, including Constraint Grammar disambiguators as well as more traditional 'Brill-taggers'. Results from a number of experiments and benchmarks are presented which show that the system is both flexible and efficient.