Title: Historical and personal recollections of Guido Altarelli,
Abstract: In this paper I will present a short scientific biography of Guido Altarelli,
briefly describing some of his most important seminal works. I will analyze in
great details the paper of the $q^2$ evolution of the effective quark
distribution: I will put this paper in a historical perspective, describing our
theoretical understanding at that time and the reasons why the paper was so
successful.