This book is concerned with the frequently-encountered notion of a paradigmatic clash between the economics of Jean-Baptiste Say and of David Ricardo, and with the more specific claim that after Ricardo’s death in 1823 Say’s opposition hardened. I demonstrate to the contrary that despite his attribution to Ricardo of extreme positions regarding doctrine and method, Say’s adherence to much of Ricardian theory – the cost dimension to value theory in particular and major elements of the growth doctrine – emerges throughout his writings; and that it is even reinforced in the 1826 edition of the Traité d’économie politique, and in the Cours complet (1828-9). The Introduction, drawing on Hollander (2001), lays out the themes constituting the ‘classical’ or Ricardian canon, provides a review of the secondary literature on the Ricardo-Say relation and establishes the plan of work.