The volume carries out a thorough analysis of the preliminary technical assessment, also taking into account the institution of assisted negotiation introduced by Decree Law No. 132/2014. On the one hand, Law No. 80/2005 determined the expansion of the subject matter of the assessment (which can now also be carried out on the person of the petitioner and the other party, if consenting) and its mode of conduct (the OTC can make assessments regarding the causes and damages related to the object of the verification); on the other hand, it introduced ex novo the institution of preventive technical advice in a conciliatory function, with a marked deflative intent of litigation. The work offers a variety of practical cases through which the main issues that have arisen regarding the applicability of compulsory a.t.p. in social security matters have been addressed.