Was a Ukrainian-French painter. He joined a progressive group of painters and was influenced by advocates of a modern Jewish literature such as David Bergelson and David Hofstein. The painters Alexander Bogomazov and Alexandra Exter were in Kiev at the time, and they taught him in 1913. In 1916 El Lissitzky and Ryback were given the task to make Jewish art memorials of Schtetls from Ukraine and Belarus. When he participated in an exhibition of Jewish paintings and sculptures in Moscow the spring 1917, his works were especially recommended. During the October Revolution in 1917, he took part in multiple activities to redefine avantgarde Yiddish culture, and therefore went to Moscow. After his father was killed by Petljura's soldiers in the Pogroms in Ukraine, he fled in April 1921 to Kaunas and in October 1921 he obtained a visa for Germany. He was in Berlin until 1924. He was member of the Novembergruppe and exhibited his Cubist pictures at both the Berliner Secession and the Juryfreien Kunstausstellung. In 1928 he had a separate exhibition in the "Galerie aux Quatre Chemins“ and in 1929 in the "Galerie L’Art Contemporain“. His style of painting had turned to the Expressionistic coloring of the School of Paris in the interwar period. Further exhibitions followed at galleries in The Hague, Rotterdam, Brüssel and Antwerpen. In 1935 he traveled to the opening of his exhibition in Cambridge. He did not live to see the retrospective exhibition in Paris arranged by Georges Wildenstein. Rybak was a contemporary of the Jewish-Russian artists Natan Issajewitsch Altman, Boris Aronson and Marc Chagall, who worked with handing down the Jewish tradition in modern art.