There are 25,000 entries and 1,500,000 words in this work of reference for the whole family. With 1200 illustrations, all chosen to illuminate the text, the encyclopaedia is unique in rejecting "dictionary" entries in favour of hard information. First published in 1981, it is the only one-volume encyclopaedia to be updated on an annual basis from the latest information in a computer-held database. This new edition contains 120 new entries; a further 500 entries have been substantially updated. The encyclopaedia uses non-technical explanations for modern scientific and technological processes and ideas as well as for its comprehensive coverage of the arts and current affairs, with particular emphasis on 20th-century achievement. New entries in the 1991 edition range from atomic force microscope and A.S.Byatt to Gulf War, Ayrton Senna and Boris Yeltsin. The new edition also contains a fully revised 32-page colour section, including maps of the world.