This book summarizes the considerable progress recently achieved in the understanding of nucleon and nuclear structure by using high energy electrons as a probe. A collection of papers discusses in detail the new frontiers of this field. Experimental and theoretical articles cover topics such as the structure of the nucleon, nucleon distributions, many-body correlations, non-nucleonic degrees of freedom and few-body systems. This book is an up-to-date introduction to the research planned with continuous beam electron accelerators.