From #1 New York Times bestselling author Christina Baker Kline comes a boldly original reimagining of the astonishing true story of two sisters in nineteenth-century North Carolina -- Kline's own distant relatives -- who married world-famous conjoined twins from Siam.

When Eng and Chang Bunker arrive in Wilkes County in 1839, they're not just a curiosity--they're a sensation. Everyone is eager to learn whether the salacious rumors about them are true. Within months, the twins have opened a general store, bought land, and begun building a plantation. Now, word has it, they're looking for wives--and in a place that thrives on gossip and legacy, their ambitions set the community on edge.

Sarah and Adelaide Yates, daughters of a once-prominent local family brought low by scandal, are drawn into their orbit. Bold, beautiful Adelaide sees in the twins' fame a chance to reclaim her future. Sarah, quiet and observant, isn't so sure. When the twins' lives become entangled with theirs, they must navigate loyalty, longing, and identity in a world where everything--including race, class, and gender--is rigidly defined.

Spanning five decades and unfolding against the backdrop of a fractured nation hurtling toward war, The Foursome is both intimate and epic: a story of love and constraint, identity and reinvention. With piercing insight and emotional precision, Kline brings to life a forgotten chapter of American history and the complex, boundary-defying marriages at its center.