J. Paul Getty

American oil magnate who was the world's richest private person in 1957 — known for legendary frugality (installing a payphone for guests) and obsessive art collecting — and who wrote How to Be Rich, which argued that wealth comes from being a better operator than competitors.

Articulated the oil businessman's philosophy: buy oil fields when they are cheap (during price depressions), operate with extreme cost discipline, and never sell assets — a simple formula executed consistently that made him the world's richest man.