The author supplements the economic market theory with a market sociology of commercial relationships. The existence of markets is the prerequisite for the creation of values. A product, a qualification, know how can be valuable, but their value is only quantified on markets. You cannot avoid them, but different markets require different relationships and behaviors. The author certainly takes on the role of an Outsider. From his empirical findings on many individual markets, he arrives at logical calculation models or strategies. The market participants can use these strategies. Markets are also bureaucratised (combating money laundering, tax evasion, errorist financing). Finally, there are microeconomic and microsociological barriers. They can dictate the behavior of market participants.