India, April 1 -- There is a particular kind of courage that corporate history rarely celebrates. The courage of the custodian. Not the founder's fury, not a revolutionary's conviction, but a much quieter, studious, and an equally strange bravery of the person who inherits a raging fire and decides, against every instinct of ego and against the lure of the blankness of a clean slate, to tend what's already been made rather than tear everything down to replace with their own vision.

When Timothy Donald Cook walked on to an Apple keynote stage in October 2011, a room held its breath in a way such high profile attendances rarely do. He never intended to be a prophet, but he knew these were the biggest boots he needed to step into. Cook was ...