The diminutive detective and his bulldog of a boss head to Las Vegas to find a runaway bride in this hard-boiled mystery by the creator of Perry Mason.   Donald Lam and Bertha Cool make for a couple of unlikely detectives. Donald is a charming ex-lawyer in his thirties who may lack brawn but makes up for it in brains. Bertha, meanwhile, is a fifty-something-year-old widow who won't take lip from anyone. She certainly won't let a bout of illness keep her down. After a stay at the sanitarium, she and Donald are off to Las Vegas for their latest case. Who needs rest?   Mr. Whitewell needs Donald and Bertha to find his son's fiancée and learn why she abruptly left town. Donald quickly gets to work with just a mysterious letter as his only lead. Soon he uncovers a scheme to swindle casinos, along with a brutal murder. Now he must determine what's going on before someone ensures he's the next member of the agency to have a long hospital stay--or worse.   "The best American writer, of course, is Erle Stanley Gardner." --Evelyn Waugh   "Gardner has a way of moving the story forward that is almost a lost art: great stretches of dialogue alternate with lively chunks of exposition, and the two work together perfectly, without sacrificing momentum." --Booklist