Going out to dinner with Juan Tamariz in Madrid is a little like accompanying a cartoon character on a journey to the real world. As Shuja Haider, the author of today’s Sunday Read, walked with him on side streets off the city center’s main drag, the Calle Gran Vía, heads turned left and right. Mr. Tamariz, 80, has been a professional magician for 52 years, and in that time, he has managed the singular feat of becoming both a household name in his home country and a living legend in magic everywhere. David Blaine has called him “the greatest and most influential card magician alive.” But in Spain, Mr. Tamariz is an icon, less like Mr. Blaine or David Copperfield and more like Kermit the Frog. In the United States, the most visible performers of magic in the late 20th century were stage illusionists who worked with big boxes and flashing lights. But Mr. Tamariz appears on stage and screen armed with little more than his two hands. He introduced Spanish viewers to the style of magi...