Alfred Day (1810–49) first published this controversial work in 1845 to substantial negative criticism. He was encouraged in his enterprise by the composer George Alexander Macfarren (1813–87) who remained a staunch supporter of Day's theories. The work begins with an introduction to Day's new approach to the figured bass and then moves on to set out his concept of diatonic (or strict) harmony and chromatic (or free) harmony. Each is discussed in depth, with sections devoted to common chords and their inversions, discords, pedals and modulation together with a large number of musical examples. This second edition of 1885 by Macfarren includes an additional preface discussing the genesis of the work and supporting its basic premise, together with an extensive appendix presenting his additions and differences of view, developed during the intervening period. Despite its complexity, Day's thinking had considerable influence on later writers on harmony.