Sigmund Freud's work was instrumental in providing a clearer understanding of how the human mind works and what motivates behavior. Freud, generally recognized as the "Father of Psychoanalysis," broke important ground in the treatment of mental and emotional disorders. His work was a breakthrough not just for the medical profession but also for such fields as criminology and sociology. Moreover, even those who disagree with many of his theories and conclusions agree that Freud's work helped cast mental illness in a new light. For the first time, people began to realize that mental disorders could be diagnosed, and often treated, much the same as physical disorders. The stigma against mental illness did not die off; it exists to this day. But the contributions of people like Freud helped mitigate that stigma.

Freud was born in what is now Pribor, Czech Republic (it was then Moravia, part of the...