The purchase of Harcourt's science, technical and medical group makes Reed Elsevier one of the world's biggest medical publishers, as well as boosting its position in the US educational market.
Reed beat Thomson Corporation of Canada and Bertelsmann to the business. Thomson will buy Harcourt's higher education group and the rest of the business Reed does not keep.
The deal was referred to the government because of competition concerns relating to the power that the merged company would wield in the market for scientific, technical and medical journals.
The UK's competition commission ruled that although the merger did raise some anti-competitive concerns, they were not significant enough to affect public interest.