Of the half-dozen central characters in The Hungry Tide, the most compelling goes by the name of Sundarbans. Her presence dominates Amitav Ghosh's enthralling new novel. Sundarbans translates as "the beautiful forest," and though she is not physically arresting, other characters can't help falling into her shadow. She is "the trailing threads of India's fabric, the ragged fringe of her sari, the achol that follows her, half wetted by the sea."

Piya Roy, a Calcutta-born American cetologist in India to study the orcaella, or fresh water dolphin, is so drawn in by Sundarbans that she almost forfeits her life to her. Kanai Dutt, a Delhi businessman who fancies himself above being charmed, also nearly succumbs. Then there is the boatman called Fokir. He may be unlearned in books and the world, but he is nearly her match in allure and primal power. But Fokir doesn't even try eluding the beautiful forest. She already owns his heart and soul, and can call for him any time.

The Sundarbans are an archipelago of islands in the Bay of Bengal. Known as "tide country," they are made up of islands, sandbars and mangrove forests, rivers, creeks and channels. "At no moment," Ghosh writes, "can human beings have any doubt of the terrain's hostility to their presence." Countless residents are killed each year by tigers and crocodiles. Those that survive face not only periodic cyclones but the humbling sight of ebb tides that literally "give birth to a forest" every day, before swallowing it again.

Along with a map at the front, and a rapturous description in the opening pages, The Hungry Tide shows its own servitude to the Sundarbans through section headings titled The Ebb and The Flood, as well as a plot in which nearly every turn is predicated by an act of nature. The story is also told in the unhurried prose to be expected in a narrative riding such eternal currents.

Not since the sodden Fens of Graham Swift's Waterland has a contemporary novel so abandoned itself to the kind of primordial literary landscape first conceived by Thomas Hardy more than a century ago. For the most part, we fancy ourselves too light-footed and plugged-in to be at the mercy of such 19th-century determinism, a self-conception as pleasing as it is naive.

Ghosh underscores this point by mixing characters native to tide country with outsiders who expect to come and go unscathed. Piya Roy, for instance, though Indian by appearance and birth, is a unilingual English-speaker from Seattle. She anticipates interacting with the landscape here no differently than she did with previous research sites in Cambodia and Vietnam. She has the gadgets of her science and the flight schedule of someone for whom the entire globe belongs in her temporary, in-passing purview. She is equally, however, a deracinated and incomplete person, and her impoverished notion of place is about to be perilously enriched.

The Hungry Tide has much on its myriad thematic mind, and its concerns, ranging from the ironies of our "translated world" to the fragility of various ecosystems, are wonderfully explored. The book is also thoughtful about human nature, especially our identities less as individuals than as social, spiritual and linguistic organisms who are far more needful of songs and myths than of careers and possessions.

This, too, is a somewhat unfashionable perspective. But Amitav Ghosh, a native of Calcutta who lives in New York, and who holds a PhD in cultural anthropology, tends to be over-praised as a postcolonial novelist and underappreciated as a writer with a capacity for the kind of ideas that are too large and complex to pass for fashions. At his best, as in The Hungry Tide, he brings a singular intelligence and sense of empathy to his stories. As he demonstrated in his previous novel, The Glass Palace, Ghosh is also a storyteller with a penchant for the broad strokes of the populist.

While the new novel isn't nearly as packed with incident, the narrative does accommodate his desire to tell adventures ranging from crocodile attacks to cyclones that leave individuals roping themselves to trees with their saris, hoping not to be blown away. Some may find the prose a bit ponderous in these sequences. But Joseph Conrad, another obvious influence, was in no greater hurry to get through the action. Given that we now tend to set our lives to movie-time, it is easy to forget that literary language trades speed for precision and resonance.

All of which makes the ending of The Hungry Tide a disappointment. It is a Hollywood-style wrap-up, with plot lines tidied and characters confessing, more or less, what they have learned from their experiences. One character, who dies so that another may live, even gets a scientific project named after him. This doesn't ring true to either Ghosh's intellect or to the setting he has created with such skill and ardour. It doesn't ring true for the Sundarbans.