The editorial-manifesto for the first issue of Klaxon - mensário de arte moderna introduces the magazine as a publication designed to “clarify and reflect on” the aftermath of the Semana de Arte Moderna event that was held in São Paulo in 1922. The document reads like a manifesto, rejects linking the Brazilian modernist movement to Italian futurism, and posits “klaxism” as an autonomous form of thought that is based on an “experimental and internationalist” point of view. The text also provides an insight into what would become the magazine’s constant inner struggle between its desire for openness to foreign ideas and its keen interest in locally produced art.   

Klaxon - mensário de arte moderna is unquestionably the first magazine to identify itself as being devoted entirely to modern art. Launched in the wake of the Semana de Arte Moderna event in São Paulo in 1922, the magazine published a total of nine issues between May 1922 and January 1923. Like other Brazilian magazines in the 1920s—Estética, Festa, A Revista, Revista de Antropofagia, Terra Roxa e Outras Terras, and Verde— Klaxon was known for its innovation and audacity, but was more innovative and bolder than its peers. The magazine’s first issue (dated May 15, 1922) already stood out for its extremely modern layout and graphic design. The arrangement of the letters on the cover, organized around a huge A to spell out the word klaxon, suggest a Dadaist collage. Fusing modern art, technology, and business, the magazine glorifies contemporary urban life and venerates the idea of progress. It was also the first Brazilian magazine to publish movie reviews. It was one of the earliest and most successful advertising vehicles in Brazilian publishing, but was unable to keep the bulk of its subscribers and advertisers because of its anti-establishment stance.       

The Brazilian poet and movie critic Guilherme de Almeida (1890–1969) was responsible for Klaxon’s graphic design. Contributors to the magazine included Mário de Andrade (1893–1945), Oswald de Andrade (1890–1954), Sérgio Buarque de Holanda (1902–82), Sérgio Milliet (1898–1966), Luis Aranha (1901–87), and Rubens Borba de Moraes (1899–1986). Between them they produced articles, worked on graphic design, and selected poems, essays, and music reviews. The magazine also had foreign correspondents: Albert Ciana in Switzerland, L. Charles Baudouin (1893–1963) in France, and Roger Avermaete (1893–1988) in Belgium. Each issue of the magazine included a print of a work by a noted Brazilian artist, such as Emiliano Di Cavalcanti, Victor Brecheret, John Graz, and others.  

The final two editions of the magazine were combined and published together as a double issue in January 1923. Cosac-Naify published a facsimile edition with an editorial commentary in 2013.