This special issue of «Quaderni Storici» examines the relations between norms, institutions and economic behaviour with regard to the increasing regulation of maritime trade in the age of mercantilism and from the perspective of those widespread illegal practices performed by social actors. It argues that, in Mediterranean and Atlantic commerce, frauds were not so much the result of a lack of norms and of institutional control. Rather, they emerged through an intense interaction between social actors and institutional powers and through a manipulative use of legal norms. See the table of contents on http://www.rivisteweb.it/issn/0301-6307