Econometrics is an academic discipline that aims at bridging economics (finance/social sciences}) and data through statistical analysis. Modern economic (social sciences) studies are inseparable from econometric analysis for evaluating existing economic theories, discovering new theories or exploring empirical evidence. In this course, we will introduce basic concepts, principles and methods of econometrics in specifying, estimating and testing empirical models. Our discussions will be mainly established in the context of linear regressions. We will also introduce the first-order asymptotic method which is essential for statistical inference, and discuss constrained estimation methods and hypothesis testing methods.