The many devoted readers of Susan Rogers Cooper's Milt Kovak mystery series have been noticed from time to time laughing out loud, even during a passage of thrilling drama. Obviously, the author is a very funny woman. And now she brings that aspect of her talent to fruition in the creation of Kimmey Kruse, stand-up comic. Kimmey is constantly assaulted by the public-bartenders, dentists, cleaning ladies - all trying to give her jokes. "I don't tell jokes! I'm a stand-up comic!" But she is just as funny offstage as on, and a character to be savored. Life at this point, however, is about as much fun as picking okra for our pint-sized comedian. While playing the Kaiser Komedy Klub in Chicago, she encounters a former lover, Cab Neusberg, whom she hasn't seen since the Laff-a-Lot club in Denver several years earlier. Planning a brief reprise, Cab arrives at Kimmey's hotel room only to expire in her arms just as things are getting interesting. That's not funny at all, and it's even less funny when Sal Pucci, the Chicago detective who catches the case, informs Kimmey that somebody gave Cab enough digitalis to kill a Buick with heart disease. Who could it have been, Ms. Kruse? As a kind of up-to-date Greek chorus with common sense, there is Kimmey's corporate lawyer friend Phoebe, a very present phone presence in whom Kimmey confides. Phoebe gives the comedian strong doses of reality and the name of the Chicago equivalent of super-lawyer Racehorse Haynes. She'll need it.