CHASING MAMMON By Douglas Kennedy (HarperCollins, $249) DOUGLAS Kennedy seems to fancy himself as a new breed of travel writer: his movements are motivated by themes, not destinations. His previous book, In God's Country, was a tour of religions in the United States' ''Bible belt''. His new book, Chasing Mammon , is a tour of financial dealing rooms and stock exchanges around the world. In six places, he talks to people in the money business: mostly foreign exchange dealers and stockbrokers. The best story is the grim tale of Stan from Stepney, in London. He worked all day, spent every spare minute drinking, and drove his wife Angela around the bend. One night, after guiltily refusing to accept her phone calls at work, he arrives home late at night, drunk, to find no Angela. But he does find a note on his pillow from her. He knows her so well he can guess what she has written without reading it: ''Taken the kids to my sister's for the weekend because you don't love me any more.'' Stan falls into a drunken stupor the moment his head hits the pillow. He does not actually read the note until he wakes up the next day. It said: ''The kids are at my sister's. I am at the Grand Hotel in Eastbourne. If you don't meet me on the beach in front of the hotel tomorrow at 9am, the marriage is over.'' ''Tomorrow'' had already come, and it was 11.30am. Stan scrambles into his car and eventually finds her in Eastbourne, but it is too late. This is easily the best-written passage in this book and this is revealing for two reasons. First, it is the only passage in which the writer does not take a prominent part, but leaves it to the characters. The rest of the book consists of the narrator'smeandering conversations with Suits, most of whom are just too boring to hold the reader's attention for half the number of pages he gives them. We meet the writer's old college friends, who are now in Wall Street, and there are financiers of various breeds he has encountered in dealing rooms in Sydney, Singapore and Budapest. They are all curiously unappealing. The blurb writer who describes this on the jacket as ''compulsively readable'' is clearly from the fiction department. Second, the Stan and Angela anecdote is written as fiction. The reader is told Angela's thoughts, the precise sensations inside Stan's alcohol-poisoned cranium and so on. One cannot help but be suspicious about what level of reality exists in the storiesin this book. The writer admits in the introduction that he has changed names, occupations, whereabouts, and ''occasionally amalgamated people's stories''. The result is that one is left with the unsatisfying feeling of never knowing whether this is journalism or fiction. The trouble with this volume is that writer Douglas Kennedy has wandered into the realm of Liar's Poker and Den of Thieves - and other people have painted far more vivid and gutsy pictures of the world of international finance than he has.