“I don’t think I ate much lunch,” said Ms. Quinn, who like Mr. Bogle would become a best-selling author. “He was spreading papers all over. He’s explaining, and I’m pushing. I thought, ‘It can’t really be this simple.’

“I took all of the stuff and read it and called him back. I wrote about the 500 Index Fund as one of the great products and have been boosting it ever since.”

As Mr. Bogle, 87, approaches his 65th anniversary in the investment industry, in July, he has been called a legend and a genius, an icon and an innovator. He founded Vanguard on the idea that a mutual fund company should be managed in the sole interest of its shareholders and he structured it as a client-owned company with no outside owners seeking profits. His launch of the first index mutual fund was also a game-changer and helped make investing more affordable for the masses.

“Jack took a job with Wellington in 1951 at the age of 22, entering an industry he would eventually transform,” Vanguard Chairman and CEO Bill McNabb said. “Since then, he has never wavered in his passion for standing up for the interests of the everyday investor.”

John Rekenthaler, a Morningstar columnist and vice president for research, said Mr. Bogle has had a greater effect on the mutual fund industry than “anybody or anything.” “He’s been the main driver of change,” said Mr. Rekenthaler, who has covered the industry for Morningstar since 1988.

“He’s had a huge impact. You can’t get any bigger.”

Investors come first

Mr. Bogle’s mission led to the launch of Vanguard in 1975 and the first index mutual fund in 1976. It took a few years for indexing and the Vanguard way to gain traction. The First Index Investment Trust was originally derided as “Bogle’s Folly.”

It wasn’t until the 1980s that indexing and Vanguard caught on. Vanguard is now the nation’s largest mutual fund company with about $3.5 trillion in assets as of May 31. Most mutual fund firms now offer index funds, which account for more than 20% of all fund assets nationwide.

“Jack is an idealist and a missionary and he is incredibly competitive,” said Jim Norris, the managing director of Vanguard International and a former research assistant for Mr. Bogle. “He believed with absolute certainty that he was right about what was best for investors.”

From the heart

Mr. Bogle, who underwent heart transplant surgery in 1996, put his new heart through a major stress test just a few days after the operation. It seems Mr. Bogle disagreed with a column Mr. Rekenthaler wrote about academic theory and efficient markets, and he let him know about it.

“He was on his recovery bed,” Mr. Rekenthaler said. “He dictated a three- or four-page letter to me and just destroyed me. He couldn’t wait.”

Mr. Bogle made his point, and Mr. Rekenthaler agreed it was a good one.

“He was mostly right,” Mr. Rekenthaler said. “It wasn’t one of my most insightful columns.”

All-weather advice

Mr. Bogle, so revered and respected by investors over the decades, was rescued from the rain by one years ago. Walking from his hotel to a client meeting in San Francisco, Mr. Bogle got caught in a downpour and was forced to use a copy of The Wall Street Journal as an umbrella. Needless to say, the paper’s coverage of Mr. Bogle was inadequate that day.

“He was getting soaked,” said Andy Clarke, a principal in the Investment Strategy Group and former research assistant for Mr. Bogle. “A cab pulled up next to him. The passenger rolled down the window and said, ‘You’re Mr. Bogle, aren’t you? Hop in.’ Turns out he was a Vanguard client who owned the 500 Index and Explorer Funds. Mr. Bogle gave him an impromptu update on both as the cab detoured to take him to his meeting.”

Staying the course

Since stepping down as Vanguard CEO in 1996 and as senior chairman in 2000, Mr. Bogle has continued to be a fierce advocate for investors, a major influence on the investment industry, and an admired and accessible presence at Vanguard’s Malvern, Pennsylvania, headquarters.

As president of Bogle Financial Markets Research Center, Mr. Bogle maintains regular office hours in the Victory Building and keeps research assistant Michael Nolan and administrative assistants Emily Snyder and Kathy Younker hopping. Mr. Bogle has written nine of his ten books since he departed as CEO, and he often speaks at conferences and other events.

“My favorite memory of Mr. Bogle is when I drove to his house with copies of his first book, Bogle on Mutual Funds, hot off the presses,” Mr. Norris said. “He was so deservedly proud of the book and I still have a picture of the two of us in his driveway holding a copy of the book. I am sure he never considered how many more books were to follow!”

In 2004, Time magazine named Mr. Bogle one of the world’s 100 most powerful and influential people. Fortune magazine, in 1999, designated him as one of the investment industry’s four Giants of the 20th Century.

“He changed investing, and changed investing for individuals,” Ms. Quinn said. “It’s an absolutely remarkable thing that he did.”

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