There was a bit of a gap between Anthony and Cleopatra’s Nile cruises and the C19th heyday of purpose-built, shallow-bottomed paddle-wheelers. This book is about the latter – delicious travelling for those able to afford it, and pale enough to be admitted to linger in those cavernous lounges, under airy awnings. (May make one feel a sudden surge of sympathy for Agatha Christie, who used her pen to bring a number of such imagined travellers to grisly ends.)