If two parents can run a family, why shouldn’t two executives run a company? We dig into the research and hear firsthand stories of both triumph and disaster. Also: lessons from computer programmers, Simon and Garfunkel, and bears versus alligators.  RESOURCES:"How Allbirds Lost Its Way," by Suzanne Kapner (The Wall Street Journal, 2023)."Is It Time to Consider Co-C.E.O.s?" by Marc A. Feigen, Michael Jenkins, and Anton Warendh (Harvard Business Review, 2022)."The Costs and Benefits of Pair Programming," by Alistair Cockburn and Laurie Williams (2000)."Strengthening the Case for Pair Programming," by Laurie Williams, Robert R. Kessler, Ward Cunningham, and Ron Jeffries (IEEE Software, 2000).EXTRAS:"The Facts Are In: Two Parents Are Better Than One," by Freakonomics Radio (2023)."The Secret Life of a C.E.O.," series by Freakonomics Radio (2018-2023).