The electric guitar became one of the defining instruments of rock music. It is used for riffs, chord progressions, melodic lines, and solos. The characteristic sound of a rock guitar is shaped not only by the instrument itself, but also by the amplifier, cabinet, and effects such as overdrive, distortion, fuzz, echo, and delay. In the 1930s, the first mass-produced instruments with electromagnetic pickups appeared, making it possible to significantly amplify the sound of the strings. In the 1950s, with the rise of rock and roll, the electric guitar became a central element of popular music. Artists such as Chuck Berry, Bo Diddley, and Buddy Holly made guitar riffs and short solos an important part of the song form.