In 2006 and 2007, houghton mifflin successively completed two large-scale mergers and acquisitions that shocked the international education community: in 2006, it merged with Riverdeep Interactive Learning Company, the largest interactive teaching provider in the United States, and changed its name to Horton Mifflin Group; In 2007, Horton Mifflin acquired three companies, namely Harcourt Education Company, Harcourt Trading Company and Greenwood-Heineman Company, the largest education publisher in Britain. As a result, Horton Mifflin Group has become one of the largest educational publishing groups in the world, with a market value of $654.38+0.2 billion.