The New York Times reports that Riverdeep, an Irish educational software company, is close to making a deal to acquire the textbook publisher Houghton Mifflin for about $3.5 billion, including debt, people involved in the negotiations said. The deal may be announced as early as today.

A merger of Houghton Mifflin and Riverdeep is expected to help the combined company compete against rivals like McGraw-Hill and Pearson. Several other textbook publishers have recently merged or are up for sale: Blackwell Publishing was acquired by John Wiley & Sons; Thomson Learning is on the block; and Wolters Kluwer's education business may also be sold soon. Talks between Houghton Mifflin and Riverdeep have gone on for months, people involved said. Riverdeep will create a new company and merge itself and Houghton Mifflin into the business. Riverdeep, which is half the size of Houghton Mifflin, is expected to take on significant debt to finance the deal.

UPDATE: The deal was made Wednesday morning.