Reading the pyramid
Maslow described this ranking in his 1943 paper "A Theory of Human Motivation." Lower needs usually come first, but the order is a tendency, not a strict rule. Most people are partly satisfied at several levels at once. Maslow never drew a pyramid himself; that picture came later from other writers. Late in life he also added self-transcendence, serving something beyond yourself, above self-actualization. Research support for a strict order is weak, and cultures differ in which needs they rank highest.