This book provides a unique reference to more than 840 covers used in Great Britain during the first month of the postage stamp. Included in the lists are known provenances and hundreds of auction estimates and realisations. With over 300 pages and more than 750 illustrations it is the most comprehensive work of its kind ever published. For the penny values, covers used up to and including 10 May are listed; for the twopenny values, adhesive and Mulready combination covers, and caricatures, all May dates are listed.