This volume provides a sample of research on the foundations of quantum mechanics and related topics by collecting the papers of the Italian scholars who attended the conference entitled The Foundations of Quantum Mechanics - Historical Analysis and Open Questions (Lecce, 1998). The perspective of the book is interdisciplinary, and hence philosophical, historical and technical papers are gathered together so as to allow the reader to compare different viewpoints and cultural approaches. Most of the papers confront, directly or indirectly, the objectivity problem, taking into account the positions of the founders of QM or more recent developments. More specifically, the technical papers in the book pay special attention to the interpretation of the experiments on Bell’s inequalities and to decoherence theory but topics on unsharp QM, the consistent-history approach, quantum probability and alternative theories are also discussed. Furthermore, a number of historical and philosophical papers are devoted to Planck’s, Weyl’s and Pauli’s thought, but topics such as quantum ontology, predictivity of quantum laws, and more, are treated.