For the next six years, Bogdanov was a major figure among the early Bolsheviks, second only to Vladimir Lenin in influence. In 1904–1906, he published three volumes of the philosophic treatise "Empiriomonizm" ("Empiriomonism"), in which he tried to merge Marxism with the philosophy of Ernst Mach, Wilhelm Ostwald, and Richard Avenarius. His work later affected a number of Russian Marxist theoreticians, including Nikolai Bukharin. In 1907, he helped organize the 1907 Tiflis bank robbery with both Lenin and Leonid Krasin.