There has been much research into the musical acoustics of the piano, including models of piano strings [520,21,72,73,134,39] and the piano hammer [467,59,167,55,463,154]. Additionally, there has been considerable work to date on the problem of piano synthesis by digital waveguide methods [439,490,493,51,39]. In this chapter (adapted from [439]), we will consider commuted waveguide synthesis of the piano. This method is capable of high quality piano synthesis at extremely low cost relative to other model-based approaches.