McGraw-Hill currently operates in 28 countries, has more than 5,000 employees globally, and offers products and services to over 135 countries in 60+ languages.

McGraw-Hill was founded in 1888 when James H. McGraw, co-founder of the company, purchased the American Journal of Railway Appliances. He continued to add further publications, eventually establishing The McGraw Publishing Company in 1899. His co-founder, John A. Hill, had also produced several technical and trade publications and in 1902 formed his own business, The Hill Publishing Company.

In 1909, the two men agreed upon an alliance and combined the book departments of their publishing companies into The McGraw-Hill Book Company. John Hill served as president, with James McGraw as vice-president. 1917 saw the merger of the remaining parts of each business into The McGraw-Hill Publishing Company, Inc.

In 1986, McGraw-Hill bought out competitor The Economy Company, then the nation's largest publisher of educational material. The buyout made McGraw-Hill the largest educational publisher in the U.S.

During the course of its history, the McGraw-Hill Companies expanded significantly through acquisition, not just within the publishing industry but also into other areas such as financial services (the purchase of Standard & Poor's in 1966) and broadcasting (the 1972 acquisition of Time-Life Broadcasting).

According to en.wikipedia.org