For years now, Emma Lathen has been writing her crisp & entertaining mysteries centering around John Putnam Thatcher, the formidable vice-president of Sloan Guaranty Trust. Miss Lathen is something of a financial wizard herself, & her talent for making the world of high finance believable & exciting is always an added dividend to her intricate ticker-tape plots. In 'Come to Dust', Thatcher is torn, grudgingly, from his Wall Street eyrie to search for a stolen $50,000 bearer bond & to track down the puzzling Elliot Patterson, model suburban husband, father & thief. The bond was slated for the coffers of Brunswick College, Patterson's alma mater, & it is to Brunswick that Thatcher goes, where he is sure both bond & Patterson will emerge. Instead, he is confronted by a callous cover-up murder & the alarming knowledge that Patterson is still on the loose. As Thatcher becomes deeply enmeshed in a grand larceny & murder among the well-heeled alumni of an Ivy League school, Miss Lathen takes wonderfully biting potshots of some of our most sacred well-heeled traditions & the & the perpetuators thereof. No one, including Thatcher, escapes unscathed as she alternately sympathizes with and mocks the very people she has created. But, in a triumph of solid suspense writing, she never lets Thatcher forget that murder is the most unforgivable of human follies. And Thatcher, for all his wry, detached view of the madness inherent in the groves of academe, is after a murderer. The killer's identity, of course, comes as a surprise, even to our august Wall Street samurai. But Thatcher has the last word-a final conclusion that is stunning for its irony: there are, it seems, some actions that are worse than murder.