This comprehensive technical note explains linear regression. It is intended for students with no prior knowledge of the topic. It is divided into nine sections, which may be assigned separately: 1. The simple linear model, 2. Fitting the model using least Squares, 3. Important properties of the least-squares regression line, 4. Summary regression statistics, 5. Assumptions behind the linear model, 6. Model-building Philosophy, 7. Forecasting using the linear model, 8. Using dummy variables to represent categorical variables, and 9. Useful data transformations. The sections correspond to stand-alone notes also available through Darden Business Publishing.