THE DUST jacket photo says it all. Jack Batten faces the camera with tweed collar up, muffler arranged, spiffy glove displayed, and hair with a shine like kitchen floors had before Betty Friedan. Straight No Chaser (Macmillan, 310 pages, $19.95 cloth) is Batten's second time out as a mystery novelist and, by gumshoe, he's dressed for the part. The photo suggests what the novel reveals: Batten himself is having a whale of a time with his lawyer-sleuth, Crang. His publishers evidently share his enthusiasm, because this is one of the most underedited books I've ever read. It's like a catalogue of brand names crossed with a PR campaign for vibrant, exciting Toronto, the only major city that people still think they're lucky to live in. Furthermore, nothing happens for ages. When a stiff finally does show up, it's on page 112. Around page 280 the pace picks up enough to prove that Batten's been hiding the right stuff all along, under the book's glitzy surface. For most readers, unfortunately, this good news will come too late. Don't give up on Crang though; two more novels are on the way and a writer with Batten's experience may get it right yet.