John Clifton Bogle

The Vanguard founder brought low-cost investing to the masses.

Most of our readers are too young to remember, but investing used to be expensive. Fund managers and brokers charged significant fees that reduced long-term returns. That millions of Americans no longer pay such costs is due in significant part to John C. Bogle Jr., who died Wednesday at age 89.

Jack Bogle created the first index mutual fund for so-called passive investing in 1976. He argued that it is foolish to pay high fees to fund managers trying to outperform the equity market since few managers actually do. Investors...