The first Picoult book that often comes to people's minds is My Sister's Keeper, and that's for good reason. This novel is her undisputed best. The story of two sisters, one of whom was born to save the other, is utterly heartbreaking. Anna isn't sick, but since her birth she's been through countless surgeries to help her sick sister, Kate. However, when her parents want her to donate a kidney to Kate, Anna pushes back as she seeks autonomy over her own body and life even though it puts her in a state of conflict with her family.
Full of twists and grounded by the all too human concerns of the family at its center, My Sister's Keeper remains the gold standard of Picoult novels.
