Enables the collector to identify the plate of most Twopence Blue stamps printed from the first six plates, i.e. those stamps with stars in the upper corners (from Plate 7 onwards the stamps had letters in all four corners, and the plate number was engraved on each stamp). To complement the 240 pages of plating photographs, Robin Cassell has written a fully-illustrated chapter on the repaired states of Plates 3 and 4.