1906, De Casseres moved to Mexico City, where he worked on the newspaper El Diario along with his friend, the cartoonist Carlo de Fornaro. In 1915, De Casseres published his first book, a collection of poetry titled The Shadow-Eater, to mixed reviews. Blanche Shoemaker Wagstaff called the volume "a welcome tribute to individualism and defiance" and the poems themselves "metaphysical meteors, searching, cataclysmic and rich in satire." A review in The New York Times favorably compared De Casseres to Walt Whitman, claiming "if his alien, highly individual genius remains unrecognized, criticism will lie upon the public, not upon him." Others, however, received it less favorably. Clement Wood, writing in the New York Call, mocked both De Casseres' book and Wagstaff's review, writing, "It must be admitted that Mr. De Casseres often uses good rhythms; what they are about is another thing. They are mainly about Nothing, as far as we can gather." By 1923, when the book was reissued by the American Library Service, a reviewer for Poetry wrote that De Casseres had lost "the simple sincerity of utterance which is the birthright of the true prophet." Starting in 1918, De Casseres reviewed books for The Sun, the editor of which (Grant M. Overton) described him as having "a dramatic gift" as a reviewer. During the same period, he reviewed books for The Bookman, which advertised that "the best of Mr. De Casseres's work appears in the Bookman" – to which The Sun responded with the claim that "the most glorious book review ever published on any page was Mr. De Casseres's in Books and the Book World, of Broome Street Straws by Robert Cortes Holliday." De Casseres also wrote humorous articles and reviews for the New York Herald and The New York Times. Politics De Casseres was interested in politics from an early age. His first signed editorial, published in 1890 when De Casseres was 17, praised the administrative changes Thomas Brackett Reed had recently made as Speaker of the House. De Casseres described himself as an individualist anarchist, and supported private enterprise though he opposed both capitalism and socialism. In October 1909, a letter to the editor of The Sun in which De Casseres called socialism the "illusion of the twentieth century" sparked a series of responses in the same publication and others. His frequent comments against socialism peppered the articles that he wrote for popular magazines and