This volume contains lectures on several topics of great current relevance in strong interaction physics. The lectures were presented at the 13th Annual HUGS at CEBAF summer school to an audience of advanced PhD students, both theorists and experimentalists. They reflect the current trend of nuclear physics research, shaped to a large extent by the experimental progress allowed by facilities such as CEBAF at Jefferson Lab, where the study of nuclei and the nucleon and its excitations by means of electron scattering can be carried out with unprecedented precision and completeness in a wide kinematic range. This volume should serve the graduate student and the researcher equally well.