Since 2004, a series entitled “Biblioteca filosofica di Quaestio”, also directed by Costantino Esposito and Pasquale Porro, has accompanied the journal Quaestio. The series includes texts, studies and research tools, which investigate, in tandem with the journal, specific issues or moments in the history of metaphysics, from its roots to the contemporary debates. The volumes of the series are subject to the same rigorous process of revision and assessment that is applied to the articles submitted to Quaestio, under the supervision of the same Advisory Board.