Sigmund Freud, Alfred Adler, CJ Jung, and William James were all brilliant and diverse theorists who made vast contributions to the science of psychological studies. These brilliant minds fueled the psychological studies of future theorists with their contrasting theoretical approaches and findings. Sometimes they collaborated to formulate concepts and agreements, but parted ways due to conceptual conflicts. Freud's psychoanalytic theory was at the epicenter of some studies, but these men, in their individuality, brought their own theoretical concepts and developed their own schools of thought from the analytical psychology of Jung, of the independent school Adler's psychotherapy, James' theory of emotion and Freud's psychoanalytic theory. The study of the mind continues as society evolves and adapts, creating new mental processes to analyze and understand. Their contributions to the psychological school of thought continue to be embraced by many modern psychologists. Sigmund Freud was an Austrian neurologist who developed the discipline of psychoanalysis, theories about the unconscious, repression, and verbal psychotherapy, a method of treating psychopathology through verbal dialogue between patient and psychoanalyst. The principles of psychoanalytic therapy are human behavior; experience and cognition are determined by innate, irrational drives that are primarily unconscious. He believed that awareness of these irrational impulses was met with psychological resistance in the form of a defense mechanism. An individual's development is determined by events during childhood and any conflicts between the conscious and unconscious. He believed that nothing an individual does is due to chance and that every piece of paper... is a science. The threshold of the 21st century will bring new psychologists, new theories and much more, but psychologists like Freud, Jung, Adler and James will never be forgotten for leading the way!ReferencesCarl Jung. (nd). In the Encyclopedia of the New World. Retrieved from http://newworldencyclopedia.orgGoodman, R. (2009). Stanford Encyclopedia of Philosophy. Retrieved from http://plato.stanford.edu/entries/james/#3Goodwin, C.J. (2008). A History of Modern Psychology (3rd ed.). Hoboken, NJ: Wiley. Institute of Transpersonal Psychology. (2011). Retrieved from http://www.itp.edu/about/william_james.phpLensenn, P. (2004). Pragmatism by William James. Retrieved from http://www.authorama.com/pragmatism-9.htmlStipkovich, A. (2011). Freud, Jung, Adler and James, Theoretical positions. Retrieved from http://www.andmagazine.com/content/and_4603.php