Almost as inevitable as war and sea and death are Douglas Reeman's novels about H.M. navy in World War II. This time it's Lieutenant Commander Steven Marshall of a captured German sub wreaking havoc of the sort that just may turn the balance at Anzio: top-secret missions inside enemy ports, commando raids, spy drops, with danger both from enemy and friend who see in his boat's shape only a hostile ship, plus enough heroism for five ordinary books. Always the hero is aged beyond his years, always there is a lady (in this case a French Mata Hari with a traitor for a husband) who saves his sanity (thus the ship, thus the war) with words like: ""This is our tomorrow, my darling."" Authentic and engrossing on the sea, as wobbly on land as a seasick marine, but one of Reeman's best and on the whole a respectable example of formula writing.