For this 1991 printing 7865 pages were revised. Hundreds of articles were amended for the reunification of Germany and a new geological time scale was introduced for all geology and palaeobiology articles. The 17 Macropaedia (knowledge in depth) volumes contain 671 articles averaging 25 pages or 34,000 words in length. The 12 Micropaedia (ready reference) volumes contain 64,673 articles and 16,939 cross-reference entries. All Macropaedia articles and about 1500 Micropaedia articles carry bibliographies. All Macropaedia articles and about 1300 Micropaedia articles are signed. The 2-volume index contains 208,163 entries and over 500,000 references. The Propaedia volume serves as a guide to the Britannica, arranged by topic, enabling the reader to carry out a plan of reading in any field of knowledge. The price quoted is for the Classic Brown (pyroxylin) version. Other bindings are the Heirloom (black fibred leather), Platinum (grey fibred leather), Full Leather (red, green or black goatskin) and the Connoisseur (red or blue morocco leather). A free copy of "Britannica World Data Annual 1991" is supplied in matching binding. Annotation source: Obálky knih