Attitude formation and change are crucial processes in human social and legal interaction. It is useful to start by defining what an attitude is and describing its importance before turning to the processes that affect attitude formation and change (also known as persuasion). Particular emphasis is placed on the dichotomy of deliberative (central, systematic) versus superficial (peripheral, heuristic) factors. After discussing the strategic use of persuasive techniques in ventures such as sales and politics, we will consider the extensive relevance of attitude change to legal processes.