Found at “Bertrand Meyer’s technology+ blog » Blog Archive Introduction to the Theory of Programming Languages: full book now freely available - Bertrand Meyer’s technology+ blog” on 2022-09-30 10:45:58.

The book is a survey of methods for language description, particularly semantics (operational, translational, denotational, axiomatic, complementary) and also serves as an introduction to formal methods. Obviously it would be written differently today but it may still have its use.