The Sun and stars rotate in different ways and at different rates of velocity, and knowledge of how they rotate is important in understanding the formation and evolution of stars and their structure. The wide variety of stars offers an equally wide variety of rotation rates and rotational evolution. From the slowly rotating stars to stars rotating close to their breakup velocities, different techniques and models have to be developed to study rotation and its effects on physical aspects of stars. In fact, one currently witnesses a complete renewal of astrophysical ideas about stellar rotation, mainly due to the development of new models including high-order effects of rotation and magnetism. This book, while not attempting to answer all questions about rotation, given that many issues still have to be further investigated, focuses on the basics and some particular aspects while aiming to show why it is important, from a physical point of view, to study stellar rotation. Based on courses given at a graduate school, these tutorial lectures will be of interest and useful to a rather broad audience of scientists and students.