Holtzbrinck Publishers, doing business as Macmillan US, keeps its readers' headiness at the ready. The company is a subsidiary of German media and publishing company Verlagsgruppe Georg von Holtzbrinck, and includes American imprints such as St. Martin's Press, Henry Holt & Company, and Farrar, Straus & Giroux. The company also publishes Scientific American magazine; the oldest continuously published magazine in the US (created in 1845) is devoted to science and technology developments, and has published the works of Albert Einstein and Jonas Salk. Macmillan is housed in Manhattan's famed Flatiron Building. The publisher does business alongside its sister firm, the London-based Macmillan Publishers Limited.