Houghton Mifflin Harcourt Journeys Houghton Mifflin Harcourt Publishing Companyeditor Houghton Mifflin Harcourt Publishing Company "Triangle Square books for young readers." Houghton Mifflin Books for children Houghton Mifflin Harcourt Publishing Company, Houghton Mifflin Harcourt Publishing Companyceditor Encyclopedia of birds for young readers