Joseph Eugene Stiglitz ( ; born February 9, 1943) is an American economist and a professor at Columbia University.
 He is a recipient of the Nobel Memorial Prize in Economic Sciences (2001) and the John Bates Clark Medal (1979).
 He is a former senior vice president and chief economist of the World Bank and is a former member and chairman of the (US president's) Council of Economic Advisers.
 He is known for his support of Georgist public finance theory and for his critical view of the management of globalization, of "laissez-faire" economists (whom he calls "free market fundamentalists"), and of international institutions such as the International Monetary Fund and the World Bank.
Douglass Cecil North (November 5, 1920 – November 23, 2015) was an American economist known for his work in economic history.
 He was the co-recipient (with Robert William Fogel) of the 1993 Nobel Memorial Prize in Economic Sciences.
 In the words of the Nobel Committee, North and Fogel "renewed research in economic history by applying economic theory and quantitative methods in order to explain economic and institutional change."
"I, Pencil" is an essay by Leonard Read.
 The full title is "I, Pencil: My Family Tree as Told to Leonard E. Read" and it was first published in the December 1958 issue of "The Freeman".
 It was reprinted in "The Freeman" in May 1996 and as a pamphlet entitled "I..
.
 Pencil" in May 1998.
 In the reprint, Milton Friedman wrote the introduction and Donald J. Boudreaux wrote the afterword.
 Friedman (the 1976 winner of the Nobel Prize in Economics) used the essay in his 1980 PBS television show "Free to Choose" and the accompanying book of the same name.
 In the 2008 50th Anniversary Edition, the introduction is written by Lawrence W. Reed and Friedman wrote the afterword.
Wassily Wassilyevich Leontief (Russian: Василий Васильевич Леонтьев ; August 5, 1905 – February 5, 1999), was an American economist known for his research on input-output analysis and how changes in one economic sector may affect other sectors.
 Leontief won the Nobel Committee's Nobel Memorial Prize in Economic Sciences in 1973, and four of his doctoral students have also been awarded the prize (Paul Samuelson 1970, Robert Solow 1987, Vernon L. Smith 2002, Thomas Schelling 2005).
Paul Robin Krugman ( ; born February 28, 1953) is an American economist who is currently Distinguished Professor of Economics at the Graduate Center of the City University of New York, and a columnist for "The New York Times".
 In 2008, Krugman was awarded the Nobel Memorial Prize in Economic Sciences for his contributions to New Trade Theory and New Economic Geography.
 The Prize Committee cited Krugman's work explaining the patterns of international trade and the geographic distribution of economic activity, by examining the effects of economies of scale and of consumer preferences for diverse goods and services.
Lawrence Robert Klein (September 14, 1920 – October 20, 2013) was an American economist.
 For his work in creating computer models to forecast economic trends in the field of econometrics in the Department of Economics at the University of Pennsylvania, he was awarded the Nobel Memorial Prize in Economic Sciences in 1980 specifically "for the creation of econometric models and their application to the analysis of economic fluctuations and economic policies."
 Due to his efforts, such models have become widespread among economists. Harvard University professor Martin Feldstein told the Wall Street Journal that Klein "was the first to create the statistical models that embodied Keynesian economics," tools still used by the Federal Reserve Bank and other central banks.
Milton Friedman ( ; July 31, 1912 – November 16, 2006) was an American economist who received the 1976 Nobel Memorial Prize in Economic Sciences for his research on consumption analysis, monetary history and theory, and the complexity of stabilization policy.
 With George Stigler and others, Friedman was among the intellectual leaders of the second generation of Chicago price theory, a methodological movement at the University of Chicago's Department of Economics, Law School, and Graduate School of Business from the 1940s onward.
 Several students and young professors that were recruited or mentored by Friedman at Chicago went on to become leading economists; they include Gary Becker, Robert Fogel, Thomas Sowell, and Robert Lucas, Jr.
The John Bates Clark Medal is awarded by the American Economic Association to "that American economist under the age of forty who is adjudged to have made a significant contribution to economic thought and knowledge".
 According to "The Chronicle of Higher Education", it "is widely regarded as one of the field’s most prestigious awards...second only to the Nobel Memorial Prize in Economic Sciences."
 The award was made biennially until 2007, but from 2009 is now awarded every year because many deserving went unawarded.
 The committee cited economists such as Edward Glaeser and John A. List in campaigning that the award should be annual.
 The award is named after the American economist John Bates Clark (1847–1938).
 Following an average wait of 22 years, approximately 30% of past Medal winners have gone on to win the Nobel, presented annually since 1969 at the Nobel Prize Award Ceremony in Stockholm.
 Moreover, 11 of the first 17 awardees (approximately 65%) went on to win the Nobel.
Paul Anthony Samuelson (May 15, 1915 – December 13, 2009) was an American economist and the first American to win the Nobel Memorial Prize in Economic Sciences.
 The Swedish Royal Academies stated, when awarding the prize in 1970, that he "has done more than any other contemporary economist to raise the level of scientific analysis in economic theory".
 Economic historian Randall E. Parker calls him the "Father of Modern Economics", and "The New York Times" considered him to be the "foremost academic economist of the 20th century".
Robert Merton Solow, GCIH ( ; born August 23, 1924), is an American economist, particularly known for his work on the theory of economic growth that culminated in the exogenous growth model named after him.
 He is currently Emeritus Institute Professor of Economics at the Massachusetts Institute of Technology, where he has been a professor since 1949.
 He was awarded the John Bates Clark Medal in 1961, the Nobel Memorial Prize in Economic Sciences in 1987, and the Presidential Medal of Freedom in 2014.
 Three of his PhD students, George Akerlof, Joseph Stiglitz, and Peter Diamond, later received Nobel Memorial Prizes in Economic Sciences in their own right.

Question: Which American economist, winner of the 1976 Nobel Memorial Prize in Economic Sciences, wrote the introduction for the 1996 reprint of "I, Pencil"?
Answer: Milton Friedman