Acquisition to Expand Thomson Scientific’s Market-leading Portfolio of Chemistry and Drug Discovery Information Solutions

STAMFORD , Conn. - September 27, 2007 - The Thomson Corporation (NYSE: TOC; TSX: TOC), a leading provider of information solutions to business and professional customers worldwide, today announced that it has acquired Prous Science, a global leader in the provision of life sciences information solutions. Prous Science will become part of Thomson Scientific. Financial terms of the transaction were not disclosed.

Scientists worldwide rely on Prous Science information solutions to enhance knowledge-based drug discovery and development. Its well-known Prous Science Integrity® portal provides access to more than 265,000 compounds with demonstrated biological activity and close to 100,000 patent family records. Prous Science has worked closely with its customers and partners to develop this highly differentiated information offering tailored to the needs of end user scientists.

In addition, Prous Science has developed strong relationships with key global medical associations and Centers of Excellence to maximize the reach of medical knowledge to specialists worldwide.

“Prous Science has built a strong global brand on its flagship solutions which have been built by scientists for scientists,” said Vin Caraher, President and CEO, Thomson Scientific. “This acquisition really complements our Pharma & Biotechnology workflow solution offerings. We look forward to working closely with the Prous Science management team to maximize synergies and add value for our customers.”

“Today’s announcement signals an excellent opportunity to accelerate our product development and innovation plan in the drug discovery space. By combining the financial strength, creativity and technology of Thomson with Prous Science, we will further drive innovations that help scientists find better solutions to their specific problems while fostering the emergence of new ideas,” said Dr. J.R. Prous, President and CEO, Prous Science.

Headquartered in Barcelona, Spain, where the company’s operations will remain, Prous Science serves key strategic geographic areas including Europe, Japan, North America and Latin America. Founded in 1958 by current President and CEO Dr. J.R. Prous, the company has more than 180 employees. Prous Science management and employees will become part of the Pharmaceutical/Chemical business unit within Thomson Scientific.

“Thomson Scientific, through its core products, including Thomson Pharma, IDDB, Derwent World Patents Index and Web of Science, has particular strengths in patent, business intelligence and investigational drug information,” said Jon Brett-Harris, Executive Vice President of Pharma/Chem Markets, Thomson Scientific. “The Prous Integrity platform complements our portfolio offering by providing unparalleled drug discovery content and unique analytic functionality for chemists and biologists.”

“Our strong background in the life sciences coupled with Thomson Scientific’s expertise in intellectual property and competitive intelligence equal a powerful value proposition for customers of both companies,” added Dr. Josep Prous Jr., Executive Vice President, Prous Science.

The Thomson Corporation (www.thomson.com) is a global leader in providing essential electronic workflow solutions to business and professional customers.  With operational headquarters in Stamford, Conn., Thomson provides value-added information, software tools and applications to professionals in the fields of law, tax, accounting, financial services, scientific research and healthcare.  The Corporation’s common shares are listed on the New York and Toronto stock exchanges (NYSE: TOC; TSX: TOC).

Thomson Scientific is a business of The Thomson Corporation. Its information solutions assist professionals at every stage of research and development—from discovery to analysis to product development and distribution. Thomson Scientific information solutions can be found at scientific.thomson.com.

About Prous Science

For more than 40 years, Prous Science has been a trusted source of information on which science depends to discover safer and more effective medicines. The company's products have evolved through the years from print journals to sophisticated electronic products incorporating the latest advances in IT. The company has complemented its Drug discovery solutions with a series of key partnerships to widen the dissemination of Medical Education worldwide by fostering relationships with key Medical Institutions and centers of excellence worldwide. For more information about Prous Science, visit www.prous.com.

This news release includes forward-looking statements which are based on certain assumptions and reflect The Thomson Corporation’s current expectations. All forward-looking statements in this news release are subject to a number of risks and uncertainties that could cause actual results or events to differ materially from current expectations. Some of the factors that could cause actual results to differ materially from current expectations include risks related to Thomson Scientific’s ability to successfully integrate Prous Science, and actions of Thomson Scientific’s competitors. Additional factors are discussed in the Corporation’s materials filed with the securities regulatory authorities in Canada and the United States from time to time, including the Corporation’s latest annual information form, which is contained in its most recently filed annual report on Form 40-F. The Corporation disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, other than as required by law.