Why are so many mediocre British mysteries imported when some first-rate ones aren't? The superb Jessica Mann, for instance, hasn't been seen here since 1975--and, if this newest suspense novel is any indication, the quality of her work has remained on the highest level. Mann's heroine this time is 40-ish Rosamund Sholto (architect, world traveler, daughter of a legendary British politico, presently unattached), who has come to Switzerland from her US home for the funeral of sister Phoebe, wife of British Deputy Prime Minister Aidan Britton. Was Phoebe's cliff-fall death an accident? Rosamund doesn't think so: after all, she feels that despicable Britton--whose rise to power was helped by his marriage--is capable of anything. Furthermore, Rosamund realizes that her own life is in jeopardy, because, like Phoebe, she knows a vile secret from Britton's Cambridge days. Soon, then, the chase is on: Rosamund is a hunted fugitive--escaping Britton's henchmen, making her way to England, bringing fatal accidents to all those who might help her along the way. And rescue comes at last in the unlikely person of Tamara Hoyland, the beautiful, gutsy mistress of a Secret Service agent: together Rosamund and Tamara will bring Britton's career to a violent end--the perfect windup to a grand, suspense-filled run in the Thirty-Nine Steps tradition. Still, Buchanesque thrills are only one aspect of the pleasure here. The characters are fully-realized, the plotting is double-layered throughout, the writing is assured and stylish. Mann is, in fact, a class act all the way--and, now that she has returned, we'll hope that everything she writes makes its way across the Atlantic in the future.