Douglass C. North, 95, a St. Louis economist who was a co-recipient of the 1993 Nobel Prize in economic sciences, died Monday at his summer home in Benzonia, Mich.

Dr. North and Robert Fogel of the University of Chicago won the Nobel Prize for research that applied economic theory and quantitative methods to explain economic and institutional change.

Dr. North spent much of his 60-year academic career pondering a simple question: Why do some countries become rich and others remain poor?

Dr. North was born in Cambridge, Mass., and earned undergraduate and doctorate degrees at the University of California, Berkeley.

He spent 33 years at the University of Washington in Seattle before coming to Washington University in St. Louis in 1983. Dr. North also wrote or cowrote 10 books and remained active in teaching and research until his health began to fail in recent years.

Washington University chancellor Mark S. Wrighton called Dr. North "the very best of what we all aspire to be - a thoughtful man, a kind colleague, a generous university citizen."

- AP