Mr. Calder and Mr. Behrens are fictional counter-intelligence agents created by the British mystery and thriller writer Michael Gilbert.
Many involve finding and dealing with British traitors or deeply embedded foreign agents; a few take place in Europe; one particularly grim one is set in World War II, during which Mr. Behrens is the bomb-maker in a failed attempt to assassinate Adolf Hitler.
In one story, the Prime Minister recalls his predecessor telling him that "E" Branch takes on the jobs "so disreputable" that no other agency will handle them.
As one adversary refers to them bitterly just before dying, both Calder and Behrens are "middle-aged cut-throats"; by the time the stories end, however, they have grown old but not noticeably softer or less capable.
After rescuing his friend, Mr. Behrens then helps Mr. Calder dig a In most of Gilbert's work, which seems urbane, ordered, and placid on the surface, there are grim undertones and hard edges not far below.
Later Colonel Weinleben takes up residence at the Seven Gables Guest House, where he goes birding and is "particularly nice with Mrs. Farmer's two young children."
"He's not a hard-boiled writer in the classic sense, but there is a hard edge to him, a feeling within his work that not all of society is rational, that virtue is not always rewarded.".