The book analyzes new forms of irregularity emerging within the application of nonstandard working contracts in Italy. An empirical research in the territorial areas of Brescia and Cagliari shows that often nonstandard forms of employment are characterized by “gray areas” very difficult to identify within a clear legal framework. Flexible contractual arrangements, in particular self-employment and labour outsourcing, are often used improperly by employers in order to lower production costs and sometimes disguise full-time subordinated working relations. The ultimate aim of the book is to draw an analytical framework over the flexibility-irregularity relationship in Italy. The theoretical assumption asserting that the increasing use of nonstandard form of employment has always a positive effect on the reduction of undeclared work, which is commonly considered as a phenomenon never intersecting with the formal work regulation, is here criticized. It is claimed, instead, the existence of a mechanism of complementarity between irregularity and flexibility in Italy.