The Encyclopaedia was acquired by Pergamon Press in 1966, the same year as the next edition was published. Despite its publication date, information within the set was not up to date beyond 1963.[25] A revised printing was made in 1973 and the encyclopedia went out of print in 1979.[26] The final edition included 12,600 pages, 28,000 articles, and 14.5 million words.