An Introduction to Statistical Learning with Applications in R, Gareth James, Daniela Witten, Trevor Hastie, Rob Tibshirani, 2021 (Springer) - A widely used textbook providing a clear explanation of linear regression from a statistical learning perspective.
Applied Linear Regression Models, Michael H. Kutner, Christopher J. Nachtsheim, John Neter, and William Li, 2004 (McGraw-Hill/Irwin) - A comprehensive, classic textbook dedicated entirely to linear regression models, offering thorough statistical details.