In 1934 de Gaulle wrote "Vers l'Armée de Métier" ("Towards a Professional Army"). He proposed mechanization of the infantry, with stress on an élite force of 100,000 men and 3,000 tanks. The book imagined tanks driving around the country like cavalry. De Gaulle's mentor Emile Mayer was somewhat more prophetic than he was about the future importance of air power on the battlefield. Such an army would both compensate for France's population shortage, and be an efficient tool to enforce international law, particularly the Treaty of Versailles, which forbade Germany from rearming. He also thought it would be a precursor to a deeper national reorganisation, and wrote that "a master has to make his appearance [...] whose orders cannot be challenged – a man upheld by public opinion".