I thought 'Lili Marleen' was from 'Hafenorgel', but I may be wrong. And I'd no idea he'd written a history of the Gulf Stream! Hamburg - yes, I think he loved the city and loved writing about it. (So do I - it's more or less where I was born and grew up.) The books I know are both about Hamburg in a way - a novel about youngsters sailing on the Elbe and growing up, and one about an associate of the legendary 15th century pirate Klaus Stoertebeker, Goedeke Michels.