The general idea behind the works presented here under the title "Lessons on Metaphysics" stems from the need to highlight and explain, to students in the various degree programs offered by this Faculty—and even those from other Faculties and university departments—some of the main themes addressed by ancient and modern metaphysics. The reader will find it easy to assimilate metaphysical concepts and problems that might sometimes seem intricate or accessible only after extensive study; thus, these Lessons have a pedagogical and introductory purpose.