Among his devoted fans, his pieces were known simply as McGs. With a "genius for illuminating that sometimes ephemeral apogee in people's lives when they prove capable of generating a brightly burning spark" (Columbia Journalism Review), Robert McG. Thomas Jr. commemorated fascinating, unconventional lives with signature style and wit.

The New York Times received countless letters over the years from readers moved to tears or laughter by a McG. Eschewing traditionally famous subjects, Thomas favored unsung heroes, eccentrics, and underachievers, including: Edward Lowe, the...