Robotics is concerned with the study of those machines that can replace or assist human beings in the execution of a task, with regard to both physical activity and decision making. The goal of the introductory chapter is to point out the problems related to the use of robots in industrial applications, as well as the perspectives offered by field and service robotics. A classification of the most common mechanical structures of robot manipulators and mobile robots is introduced. The features of the basic components for robot actuation and sensing are presented. Different control architectures are discussed. The chapter ends with a list of references dealing with topics both of specific interest and of related interest to those covered by this textbook.