In 1927, he left for Austria, leaving his family behind (his parents died in the Nazi concentration camp in Belzec).

Before mid-1936, he joined the Communist Party, and in his position as the person "responsible for transport of the National Artistic Treasure" traveled to Valencia, protecting paintings evacuated from the Museo del Prado.

He worked in the Ministry of Public Instructions and Arts, where he developed the famous "Cartilla", an ideological elementary textbook for uneducated soldiers of the Republican Army (published in October 1937 with 125,000 in the initial edition, translated to many languages).

He married Adina Amenedo and escaped with her from Barcelona, crossing to France on January 24, 1939 to avoid being arrested by the troops loyal to General Francisco Franco.

He left Europe on board the SS Winnipeg from Bordeaux, France, on August 1, 1939, with 2,200 immigrants helped by Pablo Neruda and the Chilean government.