The two were later separated and acquired by other companies, with the remnants of the original American division of Macmillan present in McGraw-Hill Education's Macmillan/McGraw-Hill textbooks, Gale's Macmillan Reference USA division, and some trade imprints of Simon & Schuster (Scribner, Free Press, and Atheneum Books) that were transferred when both companies were owned by Paramount Communications.

[1] George Edward Brett opened the first Macmillan office in the United States in 1869.

[4] George P. Brett Jr. made the following comments in a letter dated 23 January 1947 to Daniel Macmillan about his family's devotion to the American publishing industry: For the record my grandfather was employed by Macmillan's of England as a salesman.

He came to the United States with his family in the service of Macmillan's of England and built up a business of approximately $50,000 before he died.

The Bretts remained in control of the American offices of Macmillan from its creation in 1869 to the early 1960s, "a span matched by few other families in the history of United States business.

[3] Despite the strong protest of leading astronomers of the time, Macmillan US published in 1950 Imanuel Velikovsky's Worlds in Collision.

[27] Maxwell died in 1991, and Macmillan began selling properties and eventually filed for bankruptcy.

[28] Standard Rate & Data Service was sold to OAG, a sister Maxwell company.

[30] What remaining of Macmillan Inc. was eventually sold to Simon & Schuster/Paramount Communications for $552.8 million and finalized in February 1994.

[1] The online user-maintained database Jacketflap reports these constituent American publishers of Holtzbrinck's Macmillan division (August 2010):[41]