This is a course on using the Virtual Observatory (VO), an international research data infrastructure in Astronomy and Astrophysics. Starting with a brief discussion of some general concepts, it introduces some of the major client programs like TOPCAT and Aladin, together with some simple discovery protocols. A first focus topic is the query language ADQL, which is treated within the equivalent of three lectures. The second major focus of the course is the premier Python interface to the VO, pyVO, which is used to also more deeply investigate the topics treated before. The course is complemented by a number of side tracks, brief discussions of more fundamental or more specialised VO topics. The course comes with many exercises, most of which also have solutions. We hope it is suitable for both self-study and as lecture notes in teacher-led situations. In the latter case, it is designed to work as a semester-long course with two hours of lectures and lab work each per week.