Marx Brothers since he did not join the act until Gummo had departed. As with Groucho, three explanations exist for Herbert's name "Zeppo": Maxine Marx reported in "The Unknown Marx Brothers" that the brothers listed their "real" names (Julius, Leonard, Adolph, Milton, and Herbert) on playbills and in programs, and only used the nicknames behind the scenes, until Alexander Woollcott overheard them calling one another by the nicknames. He asked them why they used their real names publicly when they had such wonderful nicknames, and they replied, "That wouldn't be dignified." Woollcott answered with a belly laugh. Woollcott did not meet the
Karl Marx and the Close of His System has been seen as one of the most important discussions of Marx's economic theories, along with Rudolf Hilferding's "Böhm-Bawerk's Criticism of Marx", a defense of Marx against Bawerk. Bawerk's work is the "classical" critique of "Capital". Most subsequent critiques of Marxist economics have repeated Bawerk's arguments. Marxist economist Ernest Mandel identifies "Karl Marx and the Close of His System" as part of a literature, beginning with German social democrat Eduard Bernstein, that criticizes the dialectical method Marx borrowed from Georg Wilhelm Friedrich Hegel as "useless", "metaphysical", or "mystifying." He faults Böhm-Bawerk and the other critics for what he regards as