I downgrade this book primarily because its title strikes me as false advertising. Yes, it includes over 2500 color illustrations spread over 612 pages, but these are mostly very small images that do not allow their true appreciation as works of art. This is not an art book per se but a comprehensive historical reference work.
The vast majority of the volume is devoted to chronological listings of major artists. Individual painters and sculptors are given anywhere from a sixth of a page to a full page for a brief biography, a description of their milieu, and from one to a handful of photos of representative works. Occasional two-page spreads give readers a closer look at a particularly important piece, such as a Rembrandt self-portrait.
The book presents a fine introduction to art appreciation that illustrates the various things one must consider when evaluating artworks, such as subject, composition, perspective, light, shade, medium, color, and texture. There is a timeline at the beginning of each of the six periods of art that the book encompasses: before 1400, the 15th and 16th centuries, the 17th and 18th centuries, the 19th century, the early 20th century, and after 1945. These periods are further broken down into the predominant schools of the era. A glossary and index are included at the end.
This is by no means a bad book. As with all Dorling Kindersley titles, production values are superb. But understand what you are getting: a reference rather than an art book. On the other hand, if you want a beautiful, well-made, comprehensive book of art, I recommend "The Art Museum" by Phaidon Press, a 1,000-page oversized tome (approximately 19 x 14 x 3 inches) that weighs in at nearly 20 pounds and presents more than 2,500 carefully-selected artworks. It will cost you about $100, but your coffee table will thank you.