Washington, D.C., July 22, 2005 – The Thomson Corporation (NYSE: TOC; TSX: TOC) recently announced that it has acquired Global Securities Information, Inc. (GSI), a leading provider of online securities and securities-related information and research services. The terms of the acquisition were not disclosed.

A leader in the securities information sector, GSI has been helping the world’s pre-eminent legal and financial firms fulfill their most demanding research requirements for over 15 years. GSI’s flagship product, LIVEDGAR, combines proprietary content, award-winning search technology and domain expertise to enable legal and financial professionals to conduct online securities research and obtain source documents in a single step. GSI clients include all of the Am Law 100; 80 percent of the top investment banking firms; and all of the top U.S. accounting firms. GSI also includes 100 of the Fortune 500 companies as customers.

GSI will become part of Thomson West, the leading provider of legal research information in the U.S. and publisher of the Westlaw® online service. GSI operations and senior management, including President, Richard Harrison, Chief Executive Officer, Phillip Brown, and Chief Technology Officer, Nick Keenan, will join Thomson West. GSI has 147 employees and is based in Washington, D.C.

The acquisition will enable West to satisfy the currently unmet needs of transactional attorneys – those involved in work such as mergers and acquisitions, real estate and securities transactions. Moreover, the acquisition will further strengthen and deepen West’s relationships with large law firms, the company’s largest customer segment.

“Thomson and GSI share a common goal to help legal professionals access and use information in ways that help them serve their clients more effectively,” said Mike Wilens, President and CEO of Thomson Legal & Regulatory’s North American Legal unit. “The combined assets of GSI and Thomson bring legal professionals the world’s largest collection of securities-related data and material documents.”

“Thomson is home to the most respected and trusted brands in the legal industry,” said Phillip Brown. “We are truly excited about the opportunity to partner with Thomson West to develop powerful new services that improve how our customers put information to work for their practices.”

About GSI
Founded in 1988, Global Securities Information, Inc. is the leading provider of online securities information and research. By specializing within the securities information sector, GSI offers unmatched breadth, accuracy and currency of relevant information, as well as personal support services and research assistance. Superior understanding of the underlying information has allowed GSI to develop award-winning search, alert, and retrieval technology, delivering our expertise to clients on their desktops.

About The Thomson Corporation
The Thomson Corporation (www.thomson.com), with 2004 revenues of $8.10 billion, is a global leader in providing integrated information solutions to business and professional customers. Thomson provides value-added information, software tools and applications to more than 20 million users in the fields of law, tax, accounting, financial services, higher education, reference information, corporate e-learning and assessment, scientific research and healthcare. With operational headquarters in Stamford, Conn., Thomson has approximately 40,000 employees and provides services in approximately 130 countries. The Corporation's common shares are listed on the New York and Toronto stock exchanges (NYSE: TOC; TSX: TOC).

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