Adlerian Psychology is interpretative; it is an endeavor to understand human behavior. There are other psychologies which, like that of Adler, are dynamic, depth psychologies. Principal among these ar the systems of Freud and Jung. However, Adler has developed his science in a direction essentially different from that of Freud and Jung Some of his principles are not exclusive to his psychology nor are they original with Adler. Similar ideas, in some instances, have been expressed either in philosophy centuries ago or even in psychology shortly before the publication of his chief works