THERE IS really no such thing as a single, all-encompassing "epic of Gilgamesh," despite the existence of a number of translations that are actually conflations of various versions as much as a millenium apart in time, language, culture and sensibility. None of the early versions ever attained the kind of ascendancy that the Homeric epics did, in which any previous forms of the stories that might have existed were rendered obsolete and can no longer be found.

What we have here are two more or less new versions of Gilgamesh. One is a ranslation, highly annotated and scholarly, of the version in the Akkadian language ascribed to one Sin-leqi-unninni; the other is a historical novel by the prolific fantasist and historian Robert Silverberg. In reading these two new Gilgameshes, one must beware of thinking of one as "the original" and the other as a modern, somehow less authentic, fabrication. For Sin-leqi-unninni lived in the Middle Babylonian Period (between 1600 and 1000 B.C.), well over a thousand years after the putative historical Gilgamesh of the Sumerian king-lists, and wrote in a language -- Akkadian -- radically different from Sumerian. Both his version -- preserved on clay tablets and set down in cuneiform -- and Silverberg's are as much mirrors into their own culture as they are into that of ancient Sumer.

What is plainly apparent in both is that we are not dealing here with quaint, irrelevant fantasies. Both are intense, highly- charged, multilayered. In many wayilverberg's version is the equal of that of his celebrated predecessor.

That predecessor has never been better served than in this new translation. Maier's contribution is the meticulous scholarship that envelops the book, the copious and illuminating notes and appendices that explore fine shades of meaning and the difficulties of translating so alien a tongue and sensibility. John Gardner's contribution, completed shortly before his death, is the translation itself: lyrical, sinewy, emotionally uncompromising and rhythmically brilliant.

The most wonderful thing about this translation is the way that it's arranged on the page. It copies the columnar structure of the original tablets themselves; lacunae and surmises are clearly indicated. It's the next best thing to actually looking down at the clay tablets and understanding what they say. So effective is this means of sweeping away the obstacles to the reader's intuitive grasp of this material that the book functions as a miraculous time machine, reanimating a culture wondrously complex and strange.

The Babylonian tends to mythologize the events of his own remote history; Silverberg's intention is precisely the opposite. He writes in the received tradition of the 20th-century realistic historical novel, which, in the case of novels with Bronze Age settings, from Mary Renault (The King Must Die and others) on down, involves historicizing mythology in the light of modern archaeology and anthropology. Thus Silverberg attempts, and largely succeeds, in recreating an authentic model of Sumer; his novel is undoubtedly a far more accurate picture of Sumerian life than that of his predecessor. But then, the idea of historical precision could not have been further from Sin-leqi-unninni's mind. What's more, there are probably areas in which we know more today about ancient Sumer than Sin-leqi-unninni did.

NOT ONLY does Silverberg call all the characters by their Sumerian names (we have Ziusudra instead of Ut-Napishtim, Innana instead of Ishtar) but he brings to the surface what is present in the subtext of the Babylonian poem: the dethroning of the Great Mother by a masculine, sky-father principle, and the consequent ousting of the matriarchal order of the early Bronze Age. His Gilgamesh narrates in the first person, in the harsh, declamatory style familiar from the surviving tablets in which kings boast of their exploits. Silverberg smoothly and convincingly explains away all the supernatural elements of the myth: the monstrous Huwawa (Babylonian Humbaba) is a seismic-volcanic phenomenon; the immortality of Ziusudra is the result of the casuistry-prone blandishments of a bizarre death-haunted cult Gilgamesh finds at the end of his odyssey for the meaning of death. And the scorpion-man of the myth appears to be suffering from a disfiguring skin disease. But there's a very effective double vision at work here. For Silverberg puts the magic into the characters' minds and worldview with one hand while with the other he shows the modern reader, as it were, how the trick is done -- a difficult and admirable feat that only a writer of his caliber could bring off.

At times Silverberg incorporates actual passages from the Gilgamesh texts into his book, affording a unique opportunity to compare the two versions:

"The lion you loved: seven pits you dug for him, and seven more. The bird of many colors: you broke his wing, and he sits in the grove now, crying, 'My wing, my wing!'"

(Silverberg, p. 171) "You loved the mauve colored shepherd bird: you seized him and broke his wing. In the forest he stands crying, 'Kappi! My wing!'

You loved the lion, full of spry power; you dug for him seven pits and seven pits."

(Gardner/Maier, p. 152) As can be seen, there's little to choose from between the two versions of the same passage. One might talk about how Gardner's version sounds a tad more hieratic or how Silverberg, by changing the rhythms around, edges the passage towards a marginally more conversational tone.

When it comes to tone, there are moments in Silverberg's book that do not quite work. His Gilgamesh shares with numerous other Silverberg heroes a blustering, rampant machismo which at times feels like an uncomfortable superimposition; at one point, when Gilgamesh, addressing the reader, vehemently denies any imputation of homoeroticism in his relationship with Enkidu, he suddenly sounds more like a middle-class American male than a Bronze Age king. By contrast, Maier's notes explain explicitly that the wrestling between Gilgamesh and Enkidu is described in words with implicitly erotic double-entendres.

In all its forms, Gilgamesh is a profoundly melancholy meditation on the nature of death, and it is ironic that this translation should be John Gardner's last work. But the publication of his book and Silverberg's is a cause for celebration; each, from its unique vantage point, sheds a new and different light on one of Western civilization's timeless stories.