This book analyzes the guarantees provided for in the Public-Private Partnerships Law (Law 11.079/2004). Its starting point was the opinion of jurist and professor Kiyoshi Harada, at the request of the Precatórios Commission of the Brazilian Bar Association, São Paulo Section, published in the Boletim de Direito Administrativo (São Paulo: Editora NDJ, nº 3, pp. 308-315, Mar. 2005). In addition, substantive doctrine dealing with the constitutional and legal aspects of the guarantees offered in Public-Private Partnership contracts was consulted, which differ on the subject. The respectable side, led by Celso Antônio Bandeira de Mello, Maria Sylvia Zanella Di Pietro and Kiyoshi Harada, takes a more serious interpretation of the provisions of Law 11.079/2004 that deal with guarantees, pointing out various unconstitutionalities. On the other hand, many legal scholars take a less rigid view, such as Carlos Ari Sundfeld and Alexandre Santos de Aragão. This group believes that the guarantees offered in PPP contracts are constitutional and legal in order to encourage private individuals to invest. Thus, the legal uncertainty that Law 11.079/2004 was so keen to reduce is clear.