In this pioneering classic, psychologist Rudolf Allers demonstrates how authentic mental health is inseparable from moral and spiritual growth, arguing that the Catholic understanding of the human person uniquely explains both disorder and lasting transformation. With clarity and depth, he examines how character is formed, the forces that shape personality, and the virtues essential for steady development. Addressing self-deception, faulty ideals, and common behavioral struggles in children and adults, he offers practical guidance for parents and educators while drawing on Scripture and the wisdom of the saints. Rooted in confidence in grace, this enduring work shows that true renewal of character is always possible.