Rank was an Austrian psychologist belonging to the psychoanalytic school of thought. He was Freud's closest disciple and colleague from 1906 to 1926 during the formative years of the psychoanalytic movement. He was an expertise in many areas, some of them were art, science, and philosophy. He also become the most prolific author after Freud. As he approached the age of 40 he broke away from the orthodox psychoanalysis and prior to that in 1926 he broke away from Freud. He lived from 1884 to 1939. During this time world war 1 began, Van Gogh died, the Big Bang Theory was proposed, and Freud's, The Interpretation of Dreams came out.
He was important to psychology because he was a leader in the psychological revolution that changed the way that we see ourselves. He also started a new way of thought, and focused on the here and now, real relationships,conscious mind and will, rather than past history, transference, unconscious , and wish. He is known as an innovator in interpersonal and existential psychotherapy. The events I mentioned earlier and some more not listed, could of had a big impact on the way towards his success. Van Gogh shooting and killing himself in 1890 and the fauvist movement in art in 1900 could have introduced him to art and those events could influence the way he thought about the real world. World war 1 starting, the wright brothers flying in 1903, and the Big Bang theory being proposed in 1927, might of showed him how to world is moving forward and that maybe the past is just gone and that he shouldn't focus on that area in his work. Finally, Freud putting out The Interpretation of Dreams in 1900, could have gave Rank the introduction to Freud and he could of realized that maybe he was someone that he wanted to study under/with.