Claudi Alsina is Chair of Mathematics at the E.T.S de Arquitectura in Barcelona at the Universitat Politècnica de Catalunya. He has worked widely in mathematical research and also innovation and promotion of education. Author of numerous popular mathematics books, he is a renowned writer and conference speaker. This guide is the result of his many travels and particular way of looking at the world. With Ariel he has published Vitaminas matemáticas and El club de la hipotenusa.