Rokeach M. -1973-. The Nature Of Human Values. New York New! Free Press -

These are "preferable modes of conduct"—the behavioral means used to reach terminal goals.

These represent desirable "end-states of existence"—the ultimate life goals an individual strives to achieve.

In this foundational text, Rokeach defines a value as an "enduring belief that a specific mode of conduct or end-state of existence is personally or socially preferable to an opposite or converse mode". He posits that human values are organized into a hierarchical value system , where each value is ranked by its relative importance. The Two-Fold Classification: Terminal vs. Instrumental