Sigmund Freud (May 6, 1856 to Sept. 23, 1939) founded psychoanalysis, a treatment technique that involves the patient talking to a psychoanalyst. (Image cr: Everett - Art / Shutterstock.com)
Though his ideas were controversial, Sigmund Freud was one of the most influential scientists in the fields of psychology and psychiatry. It has been over 100 years since Freud published his theories, yet he still influences what we think about personality and the mind.