Bird does an amazing job exploring the warring emotions going on within Spencer. The teenage years can be fraught with so much uncertainty, and Bird captures this beautifully. The dialogue between the teens is realistic and shows the struggles they go through in debating how vulnerable they are willing to be as they figure out who they are.The plot is paced to perfection. I knew from the blurb that The Book of Promises is a thriller, but I began reading it with the focus on it being a YA novel. A sinister air begins to form the moment the reader sees how Molly and Spencer interact. Let’s just say it’s not good, and it sets the stage for a narrative that slowly increases in tension in very disturbing ways. I was uneasy and fearful for Spencer, and while I thought I knew how the plot should be resolved, Bird took it in a direction I couldn’t have dreamed of. I was shocked, and I loved it.Spencer and Molly’s friendship is unhealthy in so many aspects. It would have been easy for Bird to write Spencer as purely good and Molly as purely evil. Instead, Bird goes to great lengths to give the reader a complex view into what’s made each of them the young women we meet as they’re becoming young adults. It would be impossible not to identify with Spencer. The color of her skin, her sexual orientation, her gender identification are uniquely her, but there are aspects to her character that are universal. She wants to be loved. She wants to be seen. She’s awkward, and she feels trapped in circumstances beyond her control. She’s been manipulated by Molly for so long, it’s hard for her to see herself as a victim of abuse. She’s aware that Molly uses her, but she can’t separate her own feelings of low self-worth from Molly’s abuse. Spencer desperately wants to break free from the insidious cycle, but she’s a kind soul, and she realizes her actions could have a ripple effect that touches everyone she loves. Molly is so evil. Her presence in any scene gives it a malevolent feel without her uttering a word. It’s painful at times to watch her manipulate Spencer especially when it comes to the sex acts they participate in. At first, it was easy to see all her actions as malicious, but Bird doesn’t allow her character to be simply one dimensional. As the reader makes their way through the book and learns more about what makes Molly tick, it’s clear she’s just as multifaceted as Spencer. There’s no doubt she qualifies for a number of clinical diagnoses. It also becomes apparent she’s had her share of emotional abuse heaped on her.The Book of Promises took my breath away. The story is staggering in its psychological complexity. The writing is phenomenal. Bird’s character work and exploration of Spencer’s hopes, fears, and insecurities is profound. I could empathize with Spencer and her life experiences because Bird infused her with a vulnerability and goodness that had me focused on our similarities rather than our differences. There are moments that are brutal as well as those that are life affirming. The plot twist toward the end of the story knocked me for such a loop I gasped aloud. I’m a diehard romance fan, yet this YA thriller is going to be the book I’ll still be talking about years from now. I encourage you to check out this riveting novel.