Les Paul, the guitarist whose innovations in the development of the electric guitar and modern sound recording led him to be dubbed “the father of modern music,” has died at the age of 94. Paul designed one of the early “solid-body” electric guitars, and his innovations helped to improve the sound of the instruments and gain them wider acceptance in pop music. In his recordings with his wife, Mary Ford, Paul pioneered many new techniques in recording, including early versions of multi-track recording, allowing different parts to be recorded separately and then mixed together. One of their most famous singles, “The World Is Waiting For the Sunrise,” had both his guitar and Ford’s voice recorded twice and re-mixed so that they were harmonizing with themselves; he also specialized in recording voices and instruments much closer to the mike than previously thought possible. Many rock n’ roll musicians and producers learned from Paul, who helped re-define what could be done with an electric guitar and the idea that a recording could accomplish things that can’t be done in a live performance.