Ethan is an exceptionally gifted young boy, obsessed with physics and astronomy.

His single mother Claire is fiercely protective of her brilliant, vulnerable son. But she can't shield him forever from learning the truth about what happened to him when he was a baby; why Mark had to leave them all those years ago.

Now age twelve, Ethan is increasingly curious about his past, especially his father's absence in his life. When he intercepts a letter to Claire from Mark, he opens a lifetime of feelings that, like gravity, will pull the three together again.

Relativity is a tender and triumphant story about unbreakable bonds, irreversible acts, and testing the limits of love and forgiveness.

"The race towards the conclusion keeps us guessing, but ultimately, it's the beautifully drawn characters who stay with you long after the final page." - Australian Women's Weekly

"Relativity left even my cynical heart pounding . . . [many] writers could learn something from Hayes . . . wonderful and beyond inventive - if one of the precise pleasures of fiction is a glimpse at someone else's thought processes, this is indeed a marvel." - The Saturday Paper

"Pulls you into the moment like you've unexpectedly pin-dropped through Antarctic ice . . . Relativity upends expectations and holds you in its thrall as Hayes asks unsettling questions about the frailties of memory and love . . . An Australian debut not to be missed." - Readings Monthly

"A charming and fresh debut placing a family's secrets in the great expanse of the universe." - Kirkus Reviews

"Each character is a complex universe capable of love and violence. I tore through it" - Courtney Collins, author of The Burial

"An affecting, gripping debut novel about the nature of family and identity" - Mail on Sunday