Maslow's hierarchy of needs is a theory in psychology that claims human needs are prioritized in a five-tier model. At the bottom are physiological needs like food, water, warmth, and rest. Above that are safety needs, love and belonging, esteem, and self-actualization at the top. Meeting our needs is key to achieving wellness, which includes physical, emotional, social, and spiritual dimensions. Maslow studied humanistic psychology and believed understanding motivation through the hierarchy could explain human behavior.