Synopsis Musical instruments, are tools used to expand the limited scope of musical sounds--such as clapping, stamping, whistling, humming, and singing--that can be produced by a person's unaided body. Throughout the world, instruments vary greatly in purpose and design, from natural, uncrafted objects to complicated products of industrial technology. Although sirens, automobile parts, and radios have been employed in avant-garde compositions, this article mainly concerns those specialized implements intended for performing the world's conventional folk, popular, and classical music.