Winner of the 2001 Pulitzer Prize for Drama, Proof follows Catherine, a young woman grappling with the legacy of her brilliant, mentally ill father, and her own fears of inheriting his condition, with the dynamics of her controlling sister, Claire, and her father’s former student Hal, who uncovers a groundbreaking mathematical proof among his notes. 

The young but guarded Catherine grieves over the loss of her father, a famous mathematician who had become a legend among his peers for solving complicated proofs, and for retreating from public life after the onset of a psychiatric illness. Just as Catherine begins to give in to her fear that she, too, might be aging into her father’s psychosis, Catherine’s older sister Claire returns home to help “settle” family affairs and Hal, a young professor at the University of Chicago who keeps showing up at the wrong times, starts to poke around the house. What Hal discovers in an old notebook brings to light a buried secret that tests the sisters’ kinship as well as the romantic feelings growing between Catherine and Hal.

This poignant drama about love and reconciliation set on the back porch of an old house near the University of Chicago, explores themes of familial loyalty, love, hubris and who gets to be the author of their own truth.