Scientific publisher John Wiley & Sons has entered into a definitive agreement to acquire rival Blackwell Publishing. The shock announcement will see the two publishing houses join forces in a deal said to be worth £572 million.

Wiley will acquire the outstanding shares in Blackwell Publishing, a separate company from the Blackwell book shop chain, although Blackwell family members serve on both company boards.

Wiley said in a statement that it has received "irrevocable commitments from principal shareholders to sell their shares to Wiley". The deal is expected to close by the beginning of 2007. 

Blackwell revenues were approximately £210 million in 2005, on a par with Wiley's scientific, technical and medical business. William J Pesce, president and chief exec of Wiley described the deal as: "a rare opportunity with highly favourable, long term strategic implications".  Nigel Blackwell, chairman of Blackwell Publishing said: "Wiley and Blackwell are two great firms sharing the same cultural value." 

The combined publishing business will produce around 1,250 peer reviewed journals, as well as books and a strong online presence.

In May of this year Blackwell CEO Rene Olivieri denied rumours of a sell off to IWR following reports of discussions with major banks.