"A First Course in Linear Model Theory is an excellent graduate-level textbook that comprehensively covers the now classical linear regression model. Its well-structured organization, thorough mathematical review, and clear presentation of core concepts make it an excellent, self-contained resource for a first course in linear models, both for instructors and students. Moreover, the book offers numerous examples, several exercises (some with solutions), R code, and detailed proofs for key results, making it also a good resource for self-study."Carlos Cinelli, University of Washington USA, The American Statistician, October 2023.