This document provides an introduction to a doctoral thesis that investigated the use of authentic materials to develop Japanese students' communicative competence. It describes a 10-month study conducted with 92 second-year English majors at a Japanese university. The students were divided into a control group, who used textbooks, and an experimental group, who used authentic materials like films, TV shows and articles. Both groups were tested before and after using eight measures of communicative competence, and the experimental group significantly outperformed the control group on five of the tests. Qualitative data from student diaries, interviews and classroom transcripts helped explain these results by showing that authentic materials allowed students to notice a wider range of discourse features and were more motivating than textbooks.