Uncovering the hidden love triangle between novelist Elizabeth Bowen and the author's grandparents - the critically acclaimed biography with never-before-seen letters detailing the affair.

For readers who were swept up in Laura Cumming's On Chapel Sands, Daniel Mendelsohn's An Odyssey and Francesca Wade's Square Haunting.

A death in the family delivers Julia Parry a box of letters. Dusty with age, they reveal a secret love affair between the celebrated novelist Elizabeth Bowen and the academic Humphry House - Julia's grandfather.

So begins a life-changing quest to understand the affair, which had profound repercussions for Julia's family, not least her grandmother, Madeline. Julia traces these three very different characters through 1930s Oxford and Ireland, Texas, Calcutta in the last days of Empire, and on into World War II. With a supporting cast that includes Isaiah Berlin and Virginia Woolf, The Shadowy Third opens up a world with complex attitudes to love and sex, duty and ambition, and to writing itself.