The performer can direct the audience's attention in various ways. In the book, "The Secret Art of Magic", authors Eric Evans and Nowlin Craver posit that magic is directly related to warfare, and relies on the same principles for success. They reference Sun Tzu's "Art of War" to show how deception is essential to any successful campaign. Craver goes on to illustrate, through the 36 strategies, how they form a blueprint for every known method of misdirection. In World War II, British military intelligence employed stage magician Jasper Maskelyne to help devise various forms of misdirection such as ruses, deception, and camouflage.