We have no biographical information about this author, but there are detailed analyses of his book by Dr. Yankev Shatski and N. Oyslender. In 1865 a poem, entitled Di geheymnise fun yener velt oder der tkies-kaf (The secrets of the other world or the handshake) by G. M. (Warsaw: N. A. Yakobi, 1891), 140 pp., first appeared in Warsaw. One can see from the poem that Makman was an educated man and knew Polish and German literature well. The poem was the first literary work of Warsaw Jewish life in the era of the clash between Hassidism and the Jewish Enlightenment—in the 1840s and 1850s (a second printing appeared in 1891). “In the 1860s,” write N. Oyslender, “a work appeared which revised not only the Enlightened connection to Hassidic Jewry, but also generally the literary tradition of Enlightened Jewry. The problem of Hassidism took up no particularly prominent place here, just a part of the general problem that Makman undertook to write about in his work. Right there, though, was what was distinctive to the surroundings that the author depicted. From the very first sections of the poem, the peculiar coloration of the work begins to attract our attention. We have an urbane, or more accurately: a genuine Warsaw coloring.”
Sources: N. Oyslender, in Biblyologisher zamlbukh (Moscow) (1939); Y. Sh. (Yankev Shatski), in Yivo-bleter (New York) 20 (1942), pp. 125-27.