In the famous Preface to Alceste (1767), Christoph Willibald Gluck and his librettist Ranieri de' Calzabigi posited a new direction for opera. They spoke of moving beyond Baroque forms, of striving for a new naturalism in opera. They wanted, in Calzabigi's lovely phrase, to liberate the language of the heart. Taken from the height of this Reform period, the arias on this disc reveal composers exploring and experimenting, at struggle and at play, as they create the new forms that bring to opera the noble simplicity of the Classical era.