This is a specially produced original drawing with white highlights on sepia recycled card. The drawing by Steve Teasdale depicts the RAF Chief Of Air Staff Charles Portal. The bookplate carries the genuine signature of Charles Portal mounted underneath the drawing. 
There was initial opposition within Bomber Command to the idea of the Dambusters raid, with a number of key figures, including Arthur Harris, seeing it as a mad-cap scheme.
But Barnes Wallis stuck to his guns and eventually won over Air Chief Marshal Sir Charles Portal, Chief of the Air Staff, who instructed Bomber Command to proceed with the operation.
The bookplate measures approx 21 x 13 cm and would look amazing in a copy of your favourite Dambusters book.