Human beings are social beings. They form societies and manage to combine their individual skills for the advantage of the whole group. However, given a specific society, individuals have an incentive to free-ride on the effort provided by others and not contribute to the collective interests. Even more so, without restrictions, each individual has an interest to take from others what is not his. Social Organization offers a collection of four papers dealing with different aspects of how societies may deal with the problem of free-riding. The papers constitute four parts. Broadly speaking,...