Jung had several objectives in writing this book. He identified its theme as the heros struggle for freedom, the hero being one of his principal archetypal figures. Jung asserted that another purpose of the book was to conduct a scientific analysis of myths and their role in the human psyche. Finally, Jung wanted to broaden the meaning of the term libido to include all expressions of psychic energy not just the sexual drive as defined by Freud. Jung subsequently claimed that this book marked the discovery of the collective unconscious, though the term came at a later date.