Malthus's classic work, An Essay on Principle of Population, first appeared anonymously in 1798. The work was greeted with considerable excitement and caused Malthus to examine the writings and observations of innumerable other writers in order to defend his views against a host of critics. The result was a second enlarged edition, which Malthus himself calls "a new work." The further four editions that appeared in his lifetime were all to varying degrees rewritten and altered. This variorum of the first six editions reveals all the major and minor changes Malthus made in the Essay in the twenty-eight years that separate the appearance of the first and sixth editions. Considered cumulatively, these reworkings show the progression of Malthus's thinking in the light of hostile criticism. The impact of Malthus's book was far-reaching - even Darwin and Wallace acknowledge Malthus as the source of the idea of "the struggle for existence."

This variorum of the first six editions reveals all the major and minor changes Malthus made in the "Essay" in the twenty-eight years that separate the appearance of the first and sixth editions.