From 1898 until shortly after World War I, Hartmann rampaged through the photographic world, first as Alfred Stieglitz's iconoclastic hatchetman of the Photo-Secession movement, later as an unruly rebel sniping away at his mentor under the pseudonym of Caliban. One of the most prolific photographic critics of all time, Hartmann discovered many of our greatest photographers, championed photography as an art form, and sparked endless controversies about the medium.

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