The Classical-era solo concerto fit perfectly with the Enlightenment view of the individual (the concerto soloist) in collaboration with, or sometimes pitted against, the collective (the concerto orchestra). During the Baroque Era, the violin family was perfected and the piano was invented. These instruments became the beneficiaries of the concerto repertoire during the Classical Era. In this lecture, we explore double- exposition form, the adaptation of sonata form to the needs of the Classical-era solo concerto. The first movement of Mozart’s Piano Concerto no. 17 in G Major provides an illustration of double-exposition form.