Understanding personality is important in counseling and is the foundation for appropriate therapy, as a result of each person's unique personality structure, processes, growth and development, psychopathology and behavior change person. Understanding oneself and others promotes effective communication; Furthermore, the understanding and analysis of personality development remains significant since development is influenced by a number of factors, such as cognitive development, social class, family and culture. Understanding internal and external influences allows for positive approaches to helping people achieve mental health well-being. In reading chapter one of Theory and Research on Personality, by Cervone and Pervin; Personality is defined as psychological qualities that contribute to an individual's enduring and distinctive patterns of feeling, thinking, and behaving. There are several theories and approaches to understanding personality. Basically theorists must answer three simple what, how, and why questions about personality structure, development, and change. In studying personality structure it is necessary to identify the enduring psychological qualities that an individual possesses to differentiate one person from another. The process is a person's ability to change their personality and motivational aspects in a short period of time. Personality growth and development is the understanding of origin in relation to personality, one could conclude either by nature or nurture regarding the type or trait of personality one possesses. Psychopathology and behavior change according to the American psychiatrist William Glasser “most human misery is caused by people trying to control others, while, in reality, the only behavior with…… middle of paper……ttp: // search.credoreference.com.ezproxy.apollolibrary.com/content/entry/estpsyctheory/glasser_s_choice_theory/0Heredity vs. Environment - Beyond Heritability - Development, Factors, Environmental, Human, Genetic, and Miscellaneous. (2011) http://social.rank.org/pages/299/Heredity-Versus-Environment-Beyond-Heritability.Roy, J. (2006). Development of William Glasser's Ideas: A Biographical Study. (Order No. 3227052, La Sierra University). ProQuest Dissertations and Theses, 236-236 p. Retrieved from http://search.proquest.com/docview/304921549?accountid=458. (304921549) Smith, A. (2006). Cognitive processes. In The Encyclopedia of Aging. Retrieved from http://search.credoreference.com.ezproxy.apollolibrary.comSue D., Sue D. (2008). Fundamentals of Counseling and Psychotherapy. Evidence-based practices for a diverse society ISBN: 9780471433026 John Wiley & Sons Inc.