Alexander Alexandrowitsch Maximow (Russian: Александр Александрович Максимов; 3 February [O.S. 22 January] 1874 - December 4, 1928), was a Russian-American scientist in the fields of Histology and Embryology whose team developed the hypothesis about the existence of "polyblasts". Maximow is renowned for his experimental work on the unitarian theory of hematopoiesis: all blood cells develop from a common precursor cell. Maximow served as a Corresponding Member of the Russian Academy of Sciences.