On 14 February 1984 the European Parliament approved by a large majority the Draft Treaty of the European Union (DTEU), known as the "Spinelli Project," named after its rapporteur and great architect. The presentation here proposed of this initiative focuses on three points: the political design that led to the approval of the DTEU; the contents of the DTEU; the influence of the DTEU on the development of the process of European unification.