Talk about a misleading synopsis. The cover image and the blurb make it sounds as though this book is about a girl, possibly a teen. 
 It's not. It's about a grown woman, probably mid-twenties -- and if the age were the only issue that annoyed me, we'd be in much better shape here. 
 The premise of this book is actually fascinating. Hope cannot be remembered. People who see her day after day react each time as though they're meeting a stranger. Hope is so unmemorable that she seems to create holes that the subconscious works to fill. Someone who had a delicious dinner with Hope will remember being at the restaurant -- for a meal that they ate alone. She can disappear in any crowd, because as soon as she's out of sight, she's literally out of mind. 
 The parts of the book that work best are about Hope's inner life and how it is to be in the world so utterly alone, absolutely free of any restrictions or responsibilities, yet with no connections that last longer than a few hours. It makes sense that ultimately Hope would become a gifted thief. You can't exactly hold down a steady job when each day your boss thinks you're someone completely new... and it's easy to get away with crimes when eyewitnesses never remember seeing you. 
 The plot of the book centers around a creepy app called Perfection, encouraging people to become "perfect" through an endless cycle of feedback on their habits, choices, purchases, and more. Hope becomes obsessed with tracking down the people who profit from Perfection and hurting them, and ends up involved in international espionage as part of a very long manhunt. Unfortunately, much of Hope's journey has to do with her vendetta against Perfection, and it's confusing and distracting and really, very disjointed. 
 (view spoiler)[It bothered me that Hope's brain-damaged sister Grace was the only one who could always remember and recognize Hope. This is never explained. Can other people with brain injuries remember her as well? Is her condition something in her own brain, as we're led to believe? If so, why would Grace be immune from the memory impairment? You'd think Hope would want to explore this question, if she's truly interested in understanding her condition and finding a treatment, but she never even thinks about it, as far as we can see. (hide spoiler)] 
 Frankly, this book was a slog to get through. Like I said, the concept of Hope's inability to be remembered is pretty mind-warping stuff -- but the plot ends up in a pointless, long drawn-out crime caper, and the writing seems to consist mainly of strings of phrases with a noticeable lack of verbs. 
 I might have enjoyed this book more if it were about 100 pages shorter, but even so, the entire crime story left me cold. Terrific concept, weak execution. I didn't hate the book, but I can't say I particularly enjoyed it either.