Harry Karp, 43, the ""Fish"" of the title, is a divorced, private-school teacher in Cambridge, Mass., who's much given over to ""vagueings,"" a sort of mental humming that takes up pages and pages here: he muses on what the local beggars are up to, on the styles of conversation at dinner parties, on surf-casting for bluefish, on fixing a fiat on a friend's invalided heap of a car. And most readers will lose interest in ""Fish"" after a few of these ""vagueings,"" especially such pompous ones as: ""I walk into the Square evenings, I guess, to give the world's thingishness a chance to assert itself. To be reminded of the particularity of substance."" Or: ""The suppression is a recognition of the hour, but I'm not sure whether the blur is an effect of alcohol that then also impels her to call or whether she requires the pretext of alcohol in order to be able to call which she wishes to do for essentially non-alcoholic reasons."" Those readers who do continue to tag along, however, will learn how Fish gets involved with a suicidal divorcee, Gretta London, who lives with her diabetic son in her bachelor brother's house. And giving Gretta run of his seaside cottage turns out to be Fish's major action--and the book's. But even when love and illness are explored here, Engel's prose remains dimpled, often barely parsable, hopelessly clotted. So think of Bellow's Herzog, remove life from its scenes, zest from its sensibilities, the crease from its style--and you'll have a fairly good idea of this very cold Fish.