SNITTER HAS BEEN subjected to brain surgery that scrambled his perceptions, so that he is no longer quite sure where external reality ends and his private nightmares begin. He is city-bred and, before this traumatic experience, he was rather pampered, which makes it harder for him to cope without the comfortable supports of what he considers normal life.

Rowf is of sturdy peasant stock, considerably stronger and less civilized than Snitter. His problem is simpler, too: he has been thrown repeatedly into a large, metal tank filled with water, forced to swim for hours while someone keeps track of the time until he loses his strength and starts to drown. Then he is pulled out of the tank, revived and put in a cage until it is time for him to be thrown into the tank again. The purpose of all this is to determine whether he will be able to swim longer as the experience of being drowned and rescued becomes habitual.

When the two dogs escape from Animal Research, Surgical and Experimental, a government facility located in England's Lake District, they find themselves plunged into a cold, inhospitable world that they do not understand. They are fugitives, hunted and feared, foraging for scraps of food in a wild countryside where they lack the skills necessary for survival. Snitter, in whose life men have been all-powerful, thinks that the houses have been taken away as part of an experiment in which he is the subject. When snow begins to fall (the story takes from mid-October to late November), the dogs assume that men have done it to aid in their capture.

One of the things we are dealing with in the newest book by the author of Watership Down is a prolonged and minutely detailed metaphor. In their tortuous, six-week odyssey from the Buchenwald atmosphere of ARSE to a rather contrived happy ending, Snitter and Rowf move through some literary territory as mountainous as the craggy English countryside (beloved of all Wordsworthians) that is their geographical setting. Clearly, they are canine shadows of Don Quixote and Sancho Panza, but they are also echoes of Didi and Gogo in Beckett's Waiting for Godot , objects of total helplessness, playing willy-nilly a game whose rules they have not been taught. Then there are Snitter's insane monologues as he reels across the desolate landscape; the situation could be stolen from King Lear . Even the deus ex machina ending which violates the structural principles of realistic fiction but gives the reader emotional satisfaction, is introduced with a flourish, the author coming onstage and engaging in a versified discussion with the reader concerning whether he can allow his canine heroes to live. One cannot help thinking of Henry Fielding, Laurence Sterne, even Bertolt Brecht, who rescues Macheath at the end of The Threepenny Opera in a similarly implausible style.

By such devices and others, particularly by his repeatedly felt presence behind the scenes, manipulating the action and commenting on it, Adams underlines a fact that is already apparent: like them or not, his novels differ from all others being written today. He clearly aspires to the literary big leagues -- the Cervantes league, let us say. Whether he makes it or not is a decision for a later generation; at present, he seems to fall just a little short, but his failure (if, in fact, he has tried and failed) is more interesting than the neat successes turned out routinely by authors with more self-discipline and less to say.

The book is shamelessly self-indulgent at times and rather unevenly written, but its best parts leave an enduring impression, and those that violate contemporary literary canons most flagrantly usually do so enjoyably and with a clear sense of purpose.Even when Adams has two of the characters in this book discuss his previous book Waterhship Down (on pages 373/4), more than authorial vanity is involved; he has a point to make about the anthropomorphic treatment of animals in fiction and its social impact, and it is a point worth making: "Ignorant, uninstructed enthusiasm for birds and animals is worse than useless. We ought not to stir it up."

A few pages later, when he drags out of nowhere a child dying of an unspecified disease (for which animal research may find a cure), the melodramatic touch adds a significant new nuance to what might have been merely a diatribe against vivisection. From beginning to end, there is no question that this is A Novel With A Message --about man's place in the scheme of creation and particularly his relation to the animals with whom he shares this planet. But the message is given with such an intricacy of concrete detail and from so many viewpoints that (though sometimes horrifying) it is never heavy-handed.

The chief narrative problem faced by Adams was how to maintain reader interest in two dogs who wander for six weeks through a wilderness, suffering from hunger and cold, killing an occasional sheep or raiding a chickenhouse to survive, and he has solved this problem superbly, by stirring up what he says ought not to be stirred up --wrong for rabbits. He does it first by making his central characters so vivid (simultaneously doglike and humanized) that one identifies with them much more readily than with the rather two-dimensional humans who inhabit his pages. They have feelings and perceptions which we do not usually attribute to dogs -- Snitter's perception of colors, for example, perhaps a result of his operation. And they share a kind of folklore (doglore?) which includes both mythology and gallows humor.

Even more vivid than the dogs is the tod (a dialect word for "fox"), the Mercutio, Panurge and Artful Dodger of the story, whom the dogs meet in the mountains and with whom they form an alliance.The total improbability of such a partnership between natural enemies is forgotten under the impact of the tod's character. He is crafty and knowing, not given to deep reflection but wise in the ways of survival, alternately cajoling and contemptuous of his stronger but clumsy colleagues, and he speaks a dialect from the Scottish border cannily chosen to reflect at the same time his affinity to the dogs (who speak plain English) and his wild strangeness. He is one of the more memorable characters in contemporary fiction, and his harrowing death scene is touched with greatness.

But great scenes abound -- one might mention those in which the dogs, alone and perplexed in the wild, become feral; the killing of their first sheep; the disastrous encounter between a dog who has escaped from a laboratory and a man who has survived a Nazi concentration camp.

Defects include a few rather dry stretches that might have been edited down, the author's unwillingness or inability to handle humans in terms other than satire (of politicians scientists and journalists particularly) or melodrama, and the way the story is manipulated to convey (however genially and indirectly) A Moral. But Adams takes us to places where no other author has taken us and we should be grateful.

As the book weathers into a classic (if it does, and it well may), the idiosyncrasies that are a distraction on its first appearance will become part of its charm. And the prospect for the foreseeable future is that its central image --society, unable to live by its rules but also unable to work out and live by their own outlaw code -- is one in which many people will see reflected some part of themselves.