Robert Johnson was far from being the first guitar hero in History. That title could very well go to Fernando Sor, the amazing Spanish virtuoso of the late 18th and early 19th century. He was the first to take technical mastery of guitar to such a level. He performed through all of Europe for dazzled audiences. He also wrote precious pieces for our instrument, among which the famous Etudes that have been compiled in that songbook. They represent both a perfect introduction to the classical world for advanced electric or folk players, and a way for nylon players to perfect their craft and keep their fingers in good shape.