In The Confidence Code: The Science and Art of Self-Assurance-What Women Should Know, Katty Kay and Claire Shipman attempt to define confidence, to determine how it is developed, and to give guidelines for developing it. Without confidence, you lack boldness and faith in your abilities, and this dearth can greatly affect your mental health as well as your career success. Low confidence can make women appear incompetent. Their premise is that confidence is 'in alarmingly short supply' for women.