written by Daniela Bubboloni and Nazario Renzoni, published by Giunti Editore in the book series “Scientific Giunti Altas”, in January 2010 and reprinted in a new edition during 2011. Could I imagine something less photogenic than mathematics? Certainly not! However, working with the editor responsible for this volume, I discovered unexpected links between light and numbers, between different shape of shadows and thoughts. The image of rigorous mathematics changed into a concrete reality in my eyes.