This book was absolutely indispensible to me when I worked for an International Art Auctioneers. I admit this was in 1988, and a previous edition of this title, but I couldn't have done without it. I note the new edition has a 'Sherlock Holmes detection' section which is an improvement - however, I managed well without this, just due to the clear explanations in the text and illustrations. It helps to have a small magnifying spyglass handy for finer details.
Absolute godsend - hope the new edition proves as useful today as the earlier incarnation!