“In this chapter we first present the basic idea of linear regression and give a non-technical introduction. Next we cover the statistical basis of this method and discuss estimation, testing and interpretation of regression results. The third section is devoted to the presentation of an example analysis. In closing, we first discuss issues related to the causal interpretation of OLS regression coefficients and then mention some general problems encountered in linear regression and recommend further reading”. This chapter comes from The SAGE Handbook of Regression Analysis and Causal Inference which provides a comprehensive introduction to multivariate methods, focussing on regression analysis of cross-sectional and longitudinal data with an emphasis on causal analysis.