The circulation of wealth has always been one of the social and economic phenomena at the basis of legal civilization. One of the most recurrent aspects and practical applications of this phenomenon is the transmissibility of debt liability which, in its implementation, cannot fail to take into account the personal qualities of the person required to fulfill the debt.In the Italian legal system, the assumption of the debt of others is expressly governed by the Civil Code, which provides for the possibility of a modification of the passive side of the obligation through the use of legal institutions outlined in their essential features in detail, with particular reference to the effects produced and their limits of application.This brief manual, aimed at scholars of the subject, describes the legal nature, the regulatory discipline, the affinities and the differences between the instruments of assumption of the debt of others.Moreover, for the practical application of the normative discipline, there is a short form useful for the concrete drawing up of stipulations having as object delegation, expromission and assumption contracts.