Maxwell Maltz opens Psycho-Cybernetics with his foundational premise, developed through his own extensive plastic surgery practice: a person's self-image — their fundamental, largely unconscious belief about their own identity and capability — governs their behavior and life outcomes more decisively than willpower or conscious effort alone, meaning lasting behavior change requires shifting this underlying self-image rather than attempting to override it through pure willpower.

Maltz's foundational discovery, drawn from his surgical practice:

• As a plastic surgeon, Maltz observed a striking pattern: some patients who received objectively successful, transformative surgical results continued experiencing the same psychological insecurities and behavioral patterns they'd held before surgery, while other patients showed dramatic behavioral and psychological transformation following even modest surgical improvement
• This observation led Maltz to conclude that a patient's internal self-image, rather than objective physical appearance alone, primarily determined subsequent psychological and behavioral outcomes — patients whose self-image genuinely updated to reflect their improved appearance showed transformation, while patients whose self-image remained unchanged continued their prior patterns regardless of the objective physical improvement
• This foundational discovery led Maltz to extend his self-image concept beyond physical appearance to psychological and behavioral patterns generally, arguing this same self-image mechanism governs behavior and achievement across virtually all life domains, not merely physical appearance and its psychological effects

This foundational premise sets up the book's overall project: examining self-image's psychological mechanism and providing specific, practical techniques for deliberately reshaping this self-image to support desired behavior change and achievement.