For those that think it is easy for a Harvard Professor to make such pronouncements from an ivy tower, the book explains that Christensen became a professor after a prior career that included being fired from a company he helped to found.

FORBES: How Economics Can Fix Your Life

In 1924, the locals tore down the owl-haunted, "ivy-mantled" tower, fearing its imminent collapse.

WSJ: Meditation on Mortality | Elegy Written in a Country Church-Yard | Thomas Gray | Masterpiece by John J. Miller