During the late eighteenth century, a musical-cultural phenomenon swept the globe. The English square piano-invented in the early 1760s by an entrepreneurial German guitar maker in London-not only became an indispensable part of social life, but also inspired the creation of an expressive and scintillating repertoire. Square pianos reinforced music as life's counterpoint, and were played by royalty, by musicians of the highest calibre and by aspiring...