In 1988 New York City's Solomon R. Guggenheim Museum was in trouble. Money was tight; the museum's famous Frank Lloyd Wright-designed building was falling apart; exhibitions were uninspired; donors were losing interest. Enter Thomas Krens, armed with a degree in nonprofit management from Yale. As the Guggenheim's new director, he offered the board of trustees a stark choice: Preserve funds and run the museum conservatively, or attack. "If you want a vital institution," he said, "change has to take place on so many fronts that it's likely to be bewildering."
That turned out to be an understatement. Today the museum has...