Rachael Allen Books in Order

If you want a friendship-first contemporary: 17 First Kisses
If you like sharp, feminist YA: The Revenge Playbook → The Summer of Impossibilities
If you want science and a neurodiverse love story: A Taxonomy of Love
If you are here for Harley Quinn: Harley Quinn: Reckoning → Harley Quinn: Ravenous → Harley Quinn: Redemption

Rachael Allen writes young adult novels that mix big feelings with a scientist's curiosity about how people work. She grew up in rural Georgia and has said she's lived in the state her whole life. Now based in Decatur, she has built a career that moves between research labs and stories for teens.

That split life matters.

Allen earned a PhD in neuroscience and has worked as a researcher in Atlanta, with projects tied to diabetes, vision, and the brain. In one interview she described the retina as a kind of window into what is happening elsewhere in the body, which feels fitting for a novelist too. She has also said she writes after her kids are asleep, and that practical, cobbled-together rhythm seems to shape the books. They feel close to school hallways, messy kitchens, late-night texts, and the private thoughts teens do not always say out loud.

She has pointed to The Princess Diaries as the book that made her want to write young adult fiction. What grabbed her was the voice, the humor, and the sense that teenage life was worth taking seriously on its own terms. First loves, awkward mistakes, complicated friendships, and the slow work of figuring yourself out became the territory she wanted to write about.

Her debut, 17 First Kisses, arrived in 2014 and already showed what she likes to do best. On the surface it is about romance and a love triangle, but underneath it is really about grief, reputation, family strain, and the way a close friendship can bend without fully breaking. The Revenge Playbook followed with four girls taking on the football culture in their small town, bringing more of Allen's interest in sexism, loyalty, and girls refusing to stay quiet.

Science never stays in the background for long.

In A Taxonomy of Love, Allen brought that side of herself even more directly onto the page. The novel follows Spencer, a science-loving boy with Tourette syndrome, across years of friendship and almost-love with the girl next door, Hope. Allen has spoken about wanting more neurodiverse teens on YA shelves, and readers who connect with the book often respond to its mix of tenderness, messiness, humor, and honest attention to disability, grief, and desire. It became a Junior Library Guild selection and was named a Book All Young Georgians Should Read.

Then came The Summer of Impossibilities, a lake-house story about four very different girls stuck together for a season that changes them. It keeps Allen's usual interest in friendship and reinvention, but opens the frame wider, with family history, a secret society, crushes, and a summery Georgia mood running through it.

Her Harley Quinn trilogy for DC, Harley Quinn: Reckoning, Harley Quinn: Ravenous, and Harley Quinn: Redemption, pushes those same concerns into a louder register. Harley is still funny and chaotic, but Allen also makes room for STEM politics, abuse, queer love, and the question of what justice looks like when institutions fail girls. Allen has said writing Harley, a character she watched on Batman: The Animated Series growing up, was a highlight of her writing life.

Across all these books, certain threads keep showing up: friendships that matter as much as romance, Southern settings that can be loving and frustrating at the same time, and characters who do not fit neatly into the boxes other people make for them. Allen won the 2019 Georgia Young Adult Author of the Year award, and she still lives in Decatur with her children and two sled dogs. She has also shared her fondness for travel, homemade peach ice cream, and stories that let you feel dropped into somebody else's life for a while. That combination, science, heart, and a little mischief, is what makes her work feel like hers.