Introduction; 1. The emergence of commons and other forms of institutions for collective action in western Europe from the late Middle Ages onwards; 2. Common land and common rights in Flanders; 3. From rules to practice: case description, sources and methodology; 4. The choices of the commoners: understanding utility, efficiency and equity on the commons through the behavior of the commoners; 5. Dealing with dilemmas: conclusions; 6. Epilogue: the revenge of history? The return of the homo cooperans in present-day western European countries.