What would have happened if Hitler's Operation Sea Lion had gone into effect and Britain had been invaded? The author presents several of the twelve German occupation orders including the ""Most Secret Directive for Military Government of England"" and refers to Dr. Franz Alfred Six, who would have headed the Gestapo and was described by another reliable German as ""the worst of the lot""; he also looks in on Informationsheft G.B. which explored everything from the Boy Scouts (""a very good source of information for the British Secret Service"") to Lloyd's. But the Germans did not know about the British resistance movement-General Andrew Thorne's XII Corps, the Auxiliary Units trained at Coleshill and in Scotland, the radio network. . . . All stood at ready until November 18, 1944, when they were ordered to ""stand down."" David Lampe opens the secret in a book that will probably be of only momentary interest to American readers.