Leaders read for relaxation. They read for general information. Above all else, they read a lot in the field of their work. If, for example, you are the head of a shoe store chain, or if you aspire to become the head, you must read about hides, lasts, new tanning methods, merchandising, house publications, management-labor problems and developments, government reports, tariff scales, foreign trade, window dressing and decoration, real estate management, sales training, personnel selection, cost control, and hundreds of other subjects—short of cabbages and kings. For you as the leader of such a vast enterprise must keep your fingers on the pulse of all departments and keep up with the information they depend on. Competition is too keen to let you enjoy the bliss of ignorance.
~ James F. Bender, The Technique of Executive Leadership (1950)