Zadie Smith’s third novel, “On Beauty,” is full of contradictions. The one most troubling to readers? The book demands that readers slow down to appreciate its careful, witty, poetic writing, while simultaneously engrossing them so deeply in the story that you will want to finish it all in one sitting. It is a book that can be savored or devoured, depending on the reader.

“White Teeth,” Smith’s debut novel that was published when she was 24 years old, was a hugely ambitious novel that tried to tackle nearly every social issue imaginable through the interconnected lives of a plentiful cast of diverse characters. Smith interweaves her characters’ stories again in “On Beauty,” a work she says is an homage to E.M. Forster’s “Howard’s End,” but the smaller cast allows the reader to become better acquainted with each character and to each have their just say.

In fact, the frequent switches in which character is having his or her story told is part of what keeps the 443-page book moving along at such a brisk pace. The readers see the world of the story through the lens of whichever character currently has the narrator’s attention: Sometimes it is the view of a street poet from a rough part of Boston, sometimes it belongs to a British neo-conservative academic celebrity, sometimes it is that of a sturdy middle-aged black mother who watches everything she has lived for fall apart.

The two central families of the story are the Beasleys (comprising liberal Howard, a white Englishman and art history professor; Kiki, his Florida-born black wife; and their three drastically different children) and the British-via-Trinidadian Kipps (comprising Monty, the aforementioned neo-conservative professor; Carlene, his ill-fated wife; Victoria, the sexpot daughter; and a mostly-absent son.)

Conflicts abound in turns of infidelity and sexual betrayal, opposing political views, professional and academic rivalries, differing theories on what beauty is, race, religious values, and missed connections and coincidences so uncanny they seem impossible until they happen.

While center stage for most of the conflicts is Wellington, a New England liberal arts college where Howard Beasley is a professor and his longtime archrival Monty Kipps is spending the semester as a guest lecturer, the heart of the story clearly resides with Kiki.

She is the reflective soul in the book, the one most affected by the actions of all the other characters, and the character with the most personal integrity and strength. While her scenes usually lack direct clashes or scandalous sex, her thoughts regarding the actions of others help distill the story and get to the core: an important role in a novel that relies so heavily on subplots.

Smith’s conclusion to “On Beauty” differs in style from the way all loose ends were tied up and all questions were answered in the ending of “White Teeth.” Smith instead takes a more subtle approach, incorporating many of the story’s themes into one final scene but not attempting to address all the story’s concerns or conflicts at once. It is a satisfying and appropriately beautiful ending to a book titled “On Beauty.”