Assertiveness is a particular mode of communication

Communication

Communication is the activity of conveying meaningful information. Communication requires a sender, a message, and an intended recipient, although the receiver need not be present or aware of the sender's intent to communicate at the time of communication; thus communication can occur across vast...

. Dorland's Medical Dictionary defines assertiveness as:
During the second half of the 20th century, assertiveness was increasingly singled out as a behavioral skill taught by many personal development

Personal development

Personal development includes activities that improve awareness and identity, develop talents and potential, build human capital and facilitates employability, enhance quality of life and contribute to the realization of dreams and aspirations...

 experts, behavior therapists, and cognitive behavioral therapists. Assertiveness is often linked to self-esteem

Self-esteem

Self-esteem is a term in psychology to reflect a person's overall evaluation or appraisal of his or her own worth. Self-esteem encompasses beliefs and emotions such as triumph, despair, pride and shame: some would distinguish how 'the self-concept is what we think about the self; self-esteem, the...

. The term and concept was popularised to the general public by books such as Your Perfect Right: A Guide to Assertive Behavior (1970) by Robert E.