The novel begins with an illicit kiss that leads to an affair that destroys two marriages and creates a reluctantly blended family.

In a series of vignettes spanning fifty years, it tells the story of the six children whose lives were disrupted and how they intertwined.

It's so complicated to figure out who you're going to spend Christmas with.” Noting that many authors’ first novels are based on their own experience, Patchett explained that she had started her career wanting “to prove that I had this great imagination.

The famous novelist in the book, Leon Posen, uses Franny’s childhood memories.“He said that what she had told him was nothing but the jumping-off point for his imagination ...

This famous stranger’s book is a jarring act of exposure and misrepresentation of their most private moments.”[3] Prior to Commonwealth, Patchett often set novels abroad—the idea for the plot of Bel Canto came from an actual hostage crisis in Peru that she had read about in the news.

I wanted to be able to move through time and between characters...”[5] According to Ron Charles of the Washington Post “In someone else’s hands, “Commonwealth” would be a saga, a sprawling chronicle of events and relationships spread out over dozens of chapters.

We’re not so much told this story as allowed to listen in from another room as a door swings open and closed.”[3] Jeanne Brown, in the Los Angeles Times, wrote, "The present story lines are overshadowed by the events of the past, the book’s most contemporary scenes existing primarily as an entrée to older memories.”[6] Reviewers praised Patchett’s skill in engaging readers without using the fast-paced plots or exotic locations of her earlier novels.

The novel was described as “exquisite,”[7] “masterful,”[3] “breathtaking, perceptive, and poignant,”[8] “tenderhearted and tough, dryly funny and at times intensely moving,”[9] “unpretentious and ultimately heartbreaking, miniaturist but also sprawling”[6] and "full of wit and warmth",[10] as well as "a funny, sad, and ultimately heart-wrenching family portrait,"[11] and a wry but compassionate tale of step-siblings forced to become family.

Patchett has long explored the awkwardness, pain and grace that come when total strangers are forced into unexpected alliances.

This theme found its fullest expression in her 2001 best seller, Bel Canto, whose glamorous characters were taken hostage at a birthday party.

Tolerating someone else’s is harder by a coefficient of 10.”[7] As Ron Charles explained in The Washington Post, early in the novel “... we’re thoroughly invested in these families, wrapped up in their lives by Patchett’s storytelling, which has never seemed more effortlessly graceful.

This is minimalism that magically speaks volumes,”[3] Janelle Brown of the Los Angeles Times said, “Reading “Commonwealth” is a transporting experience, as if you've stepped inside Patchett’s own juice-saturated memories and are seeing scenes flash by, in all their visceral emotion.