Lahiri's novel, like her other works, takes place in India and the United States. It tracks two brothers, who are extremely close, yet very distinct in terms of personality. Subhash is older, reasoned, and level-headed. Udayan is outgoing, emotional, and reactionary. The dichotomy is established early, though the two are inextricably linked. They are raised in a small town outside of Calcutta, in the lowland. The marshy setting has two ponds that depending on the weather may be distinct, or might flood and become one. The presence of water in the novel begins on page one, and is a prominent feature in nearly every chapter through the close.
In terms of setting a tone, Lahiri is a master. From the first page to the last, there are themes that ebb and flow (water being one of the most prominent). The craft that is displayed in the novel is certainly impressive from this perspective. The novel takes on a water-ladden and heavy quality at certain points, and at others feels dry and emotionally barren, hearkening back to the flooding and receding of the two ponds. Throughout the time I was reading it, I couldn't help but lapse into my old student mindset, as if trying to define what theme I would choose to write the paper, were I to have to compose one. And there would be plenty to choose from - water, unsteadiness, pairs, border / walls, liminal spaces, ghosts, memory, life / death, science vs. arts, to name a few.
A few years ago, I had the chance to see Lahiri participate in a panel of writers. I found her quite dour, and though one speaking engagement does not even begin to point to the personality within, I did find the book similarly sullen. Hope is certainly not crushed and this novel is not overtly depressing. I did, however, find that the sense of gloom that often pervaded was at times relentless. I do believe this quality is a common feature in Lahiri's oeuvre, but maybe I was just holding out hope for an ounce more light or a bit more concession in terms of general happiness in the novel. But, that's my mistake as a reader, because this is not the Lahiri world view, at least as determined by her works.
Excuse my coloring, I do this at times (helps my categorize novels like this one with a lot of symbolism - I also did this with Anna Karenina), but I added below a few snapshots from the book after I finished reading. I think they'll help to provide a good example of what the author does with language and how she sets up various scenes. I've included passages that are primarily water-oriented, though a few others are there as well. There may be a few spoilers as some pages are from later in the book, so if you're super plot-oriented, stick to the first two photos.