It wasn’t until I was deep into this novel that I had read one of Neal Stephenson’s early novels, “Zodiac,” making me one of the few readers of that environmental thriller (echoing the author’s autobiographical note here). “Snow Crash” has the same smart-alec tone of his earlier novel, but it’s far more enjoyable — its mixture of computer technology, linguistic theory, and Sumerian mythology makes for a fascinating read. I’m not sure either his science or mythology would hold up under close scrutiny, but if the ride’s the thing, this novel delivers.