John R. Commons's Investigational Economics: introduction (W.J. Samuels). Comparison between the Parsons edition and the original manuscript of the Economics of Collective Action (P. Fajnzylber, D. Heidt and M. Johnson). A comparison between common's Legal Foundations of Capitalism and Economics of Collective Action (P. Fajnzylber, D. Heidt and M. Johnson). Investigational Economics (J.R. Commons).