As Mason Gaffney bicycled to a Boy Scout meeting in 1940, a chauffeur-driven car clipped him, leaving him with injuries that kept him bedridden for months. During his convalescence his mother, appreciating his restless intellectual curiosity, gave him books to read, including complex tax policy textbooks in which he learned about Henry George, whose late-19th-century ideas helped spark the Progressive movement.

The young Mr. Gaffney recovered; graduated from New Trier High School in Winnetka, Ill., in 1941 as his class valedictorian (he was also an Eagle Scout); and went on to become an academic economist who for decades led the Georgist movement, which promotes taxing only land as the most effective, efficient and environmentally sound way to finance government.