Childhood trauma and its lifelong implications are central to what starts out as a contemporary naturalistic novel but soon morphs into something much darker.
Yanagihara pushes genre boundaries by overlaying an exaggerated, fairy tale sensibility to the story of an orphaned child, Jude, who must overcome terrible odds in search of a better life.
"I wanted the book to be something chimeric. It's sort of half-cat, half-dragon. I wanted the reader to feel a little bit off kilter and untethered the entire time."
Revelations of the horrors Jude suffered as a child are drip-fed during the book in harrowing detail, that one critic described as "gratuitous". Yanagihara says hyper-realism was her aim and she resisted her editor's suggestion to cut some of the violent scenes to spare the reader.
"I wanted there to be a greatness of suffering, a greatness of love, a greatness of sorrow and a greatness of joy," she says. "Jude's life may be unbearable to us but that doesn't mean it's not possible. There are extreme lives everywhere. I've always thought of this as a very American book because it's such a vast country with so many places for strange lives to hide.
"It just became an absurd calculation like, 'If I cut out three scenes is that enough? If I cut out five scenes is that enough?' Readers want to feel the strength of the authorial hand.
There are some who won't be able to stay in for the ride and that's fine, but you have to reward the readers who do with a book that's complete in its construction.
"You don't want to be provocative for the sake of being provocative but I do think it's the role of the author to have something urgent to say. If you don't, you probably shouldn't be doing it at all."
Yanagihara says its length is part of the hypnotic quality of the book; it demands a great deal of time and emotional commitment so readers become intimately invested in the characters' lives in a "particular, claustrophobic way".
She relentlessly dissects the psychological effects of trauma, to time and again reveal startling truths. Remarkably, her insights were not the result of research or personal experience but simply by exploring her own imagination.
"It all seemed very logical to me that this is how Jude would try to deal with it. He is someone who is carrying a great mountain of shame. With him, it comes out in self-harm because he was never encouraged to turn that anger outwards. Any trauma that is unexpressed becomes corrosive."
Yet Yanagihara is cynical about the extent to which talk therapy can help. She's never been to therapy and says one thing that makes her suspicious about psychology is that it's the only medical field to take the view that life is always the answer to life.
"I just don't agree. You feel there is a point after which mental suffering becomes too great to have a life with meaning."
Art had a crucial influence on Yanagihara. An avid art collector, she used about 20 images as a "tonal sound check" while writing the book. Most important was Diane Arbus' The backwards man in his hotel room. She recalls first seeing the image and perceiving it as a "wonderful evocation" of loneliness.
"I thought I would someday write text to accompany it and it ended up being this book."
New Zealand and Australia are Yanagihara's first literary festival appearances. Time off is rare for the full-time magazine editor who wrote A Little Life in just 18 months at nights and weekends. Like her characters, Yanagihara enjoys a single, child-free lifestyle with a group of similarly placed friends. "I swim and go to galleries but mostly I'm just sitting around with my friends, shooting the shit, which is the best way to spend time."
Hanya Yanagihara appears at the Auckland Writers Festival at the Aotea Centre on Friday, May 13 at 2.30pm and with others on Sunday, May 15 at 3pm. writersfestival.co.nz
