Concepts are the fundamental building blocks of human thought. They represent a constant set of essential characteristics of an object class, which might develop and change with time. They are integral to all aspects of cognition. Concept learning helps a learner in contrasting and comparing categories or groups that have concept-relevant features with those categories or groups that do not contain these features. There are two components of a concept, which includes attributes and a rule. Concepts in psychology aim to understand people and the reasons behind their behavior. Ecological, biological, environmental and psychodynamic factors all play a role in the development of psychological concepts. This book presents a psychological overview of concepts in the most comprehensible and easy to understand language. It is appropriate for students seeking detailed information in this field of study as well as for experts.