DAVID CRADDOCK began his working life at sea as a cadet with P&O during which time he had plenty of practice with the signal exchange that would become the title of this, his first book. A subsequent career as a graphic designer in the museums and heritage sector and an abiding interest in our maritime history has led him to explore the theme of visual communication at sea drawing on the twin strands of his own experience. He is a member of the Society for Nautical Research and has recently become a trustee of the Britannia Museum at the Royal Naval College, Dartmouth.