This document provides an introduction and overview of corpus linguistics. It defines corpus linguistics as the study of language through large collections of authentic texts stored electronically. The document discusses the history and development of corpus linguistics. It also outlines some key principles of the corpus approach, including that it is empirical, uses large principled text collections, utilizes computer analysis, and employs both quantitative and qualitative techniques. Examples are provided to illustrate how corpus analysis can provide insights into patterns of language use and inform language teaching.