Aldo Bini, Italian, 1915 - 1993
I can't tell you too much about Aldo Bini. He was a respected, solid, professional cyclist, winning a good handful of classics and several stages of the Giro. He came second in the 1938 Tour, supporting his team leader and the eventual winner - Gino Bartali.
If truth be told, this photo is not included on this site because of Aldo, or even because of his extraordinary muscle definition. It is included because it clearly shows his second generation Vittoria Margherita derailleur with its two distinctive chain-guiding-paddles mounted above the chainstay.
(Source gallica.bnf.fr/ Bibliothèque nationale de France)