In this chapter economic aspects of constitutions are explored. Basically there are three. Constitutions, firstly, act as a condition for markets and the overall economy: they are, most of the time, criticial preconditions for economic development by the - predictable - laws they generate and the protection they offer for property and capital). Secondly constitutions act as a factor in markets and the economy. They, for instance, lower transaction costs. And. thirdly, constitutions act as a catalyst in economic relations, e.g. by boosting mutual trust.