The publication is an updated English version of a German text published in 1999, now reflecting the state of law and literature in spring 2003. Its starting point is the problem of coordination to be solved in every modern economy, which is characterised by a high degree of division of labour. The central issue is the order-political fundamental decision of the new Federal Constitution (in force since 1 January 2000) that economic activity should be coordinated by the market (competition) as well as its concretisation, completion and relativisation on the levels of constitution and legislation. The sketch of the economic constitutional law is followed by an overview of crucial legal provisions on open markets, economic supervision, money policy, macroeconomic policy, spatial planning, environmental protection, infrastructure, structural policy and social policy.