Julian Lincoln Simon (February 12, 1932–February 8, 1998) was professor of business administration at the University of Maryland and a Senior Fellow at the Cato Institute. He wrote many books and articles, mostly on economic subjects. He is best known for his work on population, natural resources, and immigration. His works are often quoted by libertarians and have sometimes been described as cornucopian.
His book The Ultimate Resource , later reissued as The Ultimate Resource 2 , is a criticism of the conventional wisdom of population growth and resource consumption. In it, Simon challenged the notion of a pending Malthusian catastrophe — that an increase in population has negative economic consequences; that population is a drain on natural resources; and that we stand at risk of running out of resources through over-consumption. His critique was praised by Nobel Laureate economist Friedrich Hayek, but also attracted many critics, such as Paul R. Ehrlich.
A wager between Julian Simon and Paul Ehrlich was made in 1980 when they bet on a mutually agreed upon metric of resource scarcity, using the price of metals. Simon won the bet. He proposed that they renew the bet since Ehrlich continued to claim that the price of metals would rise; Ehrlich refused. Simon proposed that they bet on a metric for human welfare. Ehrlich offered Simon a set of 15 metrics over 10 years, victor to be determined by scientists chosen by the president of the NAS in 2005. There was no meeting of the minds, because Simon felt that too many of the metrics measured attributes of the world not directly related to human welfare, e.g. the amount of nitrous oxide in the atmosphere.  
Simon was one of the founders of free-market environmentalism. An article profiling Julian Simon in Wired magazine inspired Bjørn Lomborg to write the revisionist environmental book The Skeptical Environmentalist.
Simon was also the first to suggest that airlines should provide rewards for travelers to give up their seats on overbooked airlines rather than arbitrarily keep certain passengers off the plane.
Simon was an omnivorous reader, and took some steps toward writing a memoir, A Life Against the Grain, which was published by his wife after his death. He died at the age of 66.
- The Economic Consequences of Immigration into the United States
- Effort, Opportunity, and Wealth: Some Economics of the Human Spirit
- Good Mood: The New Psychology of Overcoming Depression ISBN 0812690982 (Forewords by Albert Ellis and Kenneth Colby )
- The Hoodwinking of a Nation ISBN 1560004347
- A Life Against the Grain: The Autobiography of an Unconventional Economist ISBN 0765805324
- Scarcity or Abundance? A Debate on the Environment
- The Philosophy and Practice of Resampling Statistics
- Resampling: A Better Way to Teach (and Do) Statistics (with Peter C. Bruce)
- The Science and Art of Thinking Well in Science, Business, the Arts, and Love
- The Ultimate Resource II ISBN 0691003815
- Economics of Population: Key Modern Writings ISBN 1852787651
- It's Getting Better All the Time : 100 Greatest Trends of the Last 100 Years by Stephen Moore, Julian Lincoln Simon ISBN 1882577973 manuscript finished posthumously by Stephen Moore
- Kenneth N. Gilpin. "Julian Simon, 65, Optimistic Economist, Dies." The New York Times. February 12, 1998. B11.
- Writings by Julian L. Simon Available on WWW
- Liberty Institute First Annual Julian L. Simon Memorial Lecture
- The Simon Market in Science Claims
- Julian Simon's Bet With Paul Ehrlich
- Julian Simon Remembered It's A Wonderful Life
- FMN and Heartland: Remembering Julian Simon
- Many of the writings of Julian Simon are available online at: http://www.juliansimon.org/