Psychoanalysis is a set of psychological and psychotherapeutic theories and associated techniques originally popularised by Austrian physician Sigmund Freud and stemming partly from the clinical work of Josef Breuer and others. Since then psychoanalysis has expanded and been revised reformed and developed in different directions.

This was initially by Freud's colleagues and students such as Alfred Adler and Carl Gustav Jung who went on to develop their own ideas independently from Freud. Later neo-Freudians included Erich Fromm Karen Horney Harry Stack Sullivan and Jacques Lacan.

The basic tenets of psychoanalysis include the following:

1.Besides the inherited constitution of personality a person's development is determined by events in early childhood;

2.Human attitude mannerism experience and thought is largely influenced by irrational drives; Introduction to Psychoanalysis (German: Vorlesungen zur Einführung in die Psychoanalyse) is one of the most famous works of Sigmund Freud..