The fol­low­ing is an excerpt from “Sleights of Minds: What the Neu­ro­science of Mag­ic Reveals about Our Every­day Decep­tions.” by Stephen L. Mack­nik and Susana Mar­tinez-Conde with San­dra Blakeslee, pub­lished by Hen­ry Holt and Co., LLC © 2010 by Stephen L. Mack­nik and Susana Martinez-Conde. Visu­al illu­sions are fas­ci­nat­ing. They have both been used by…