
The Delta Codex
$40.38
- Hardcover
288 pages
- Release Date
15 September 2026
Summary
A girl whose subconscious contains dangerous ancient knowledge finds her voice in this “gripping…emotionally resonant” (School Library Journal, starred review) middle grade sci-fi fantasy perfect for fans of Diana Wynne Jones and Scott Reintgen.
Is there safety in silence?
In the city of Danak-Tol, children known as codexes are chosen to safeguard echoes—fragments of ancient knowledge too valuable to destroy but too dangerous to use. Forbidden to speak lest she…
Book Details
| ISBN-13: | 9781665963572 |
|---|---|
| ISBN-10: | 1665963573 |
| Author: | Deva Fagan |
| Publisher: | Simon & Schuster |
| Imprint: | Atheneum Books for Young Readers |
| Format: | Hardcover |
| Number of Pages: | 288 |
| Release Date: | 15 September 2026 |
| Weight: | 358g |
| Dimensions: | 25mm x 140mm x 210mm |
| Audience Age: | 10-99 |

You Can Find This Book In
Critics Review
- “In this gripping science fiction thriller, Fagan reiterates her strength as a masterful world builder… . Fans of Scott Reintgen and Fagan’s earlier works will eagerly embrace this thought-provoking, emotionally resonant novel.” – School Library Journal, starred review
“Delta’s journey from parroting propaganda to thinking for herself is the kind of compelling and believable that has brought decades of readers to Lois Lowry’s The Giver and newer generations to Donna Barba Higuera’s Alebrijes.” – Shelf Awareness
“Readers will be drawn in by the warm, wholesome cast of characters. A hopeful, exciting, and action-packed adventure.” – Kirkus
“[E]lectric … . Concise, economical storytelling and steady pacing mold a vast dystopian world whose charismatic leads evoke protective warmth from the jump.” – Publishers Weekly
“It’s an exquisitely crafted sci-fi mystery, and though suspense and action abound, it makes time for humorous asides and moments of wonder. An extensive history and mythology flesh out the fascinating world, and Delta’s internal journey feels as profound as her external odyssey. An exhilarating examination of the power of stories, truth, and kindness.” – Booklist
“A unique setting with an intriguing history, a dystopian society of secrets and hierarchies, and a tween learning on the fly just how bold she can be—there’s a lot here to recommend to sci-fi fans.” – BCCB
“From the intriguing premise to the rapidly unspooling mystery of the bloodstorms and how they relate to the Founders, Fagan keeps things moving in this energetic sci-fi tale, where every ally Delta makes takes her one step closer to understanding what has been placed in her head. The stakes get higher throughout, so that by the end planetary survival is on the line and the deceit has been stripped from every bastion Delta’s life is founded on, leaving her the better for it.” – The Horn Book Magazine
Deva Fagan
Deva Fagan writes fantasy and science fiction for all ages. When she’s not writing, she spends her time reading, doing geometry, playing video games, hiking, and drinking copious amounts of tea. She is the author of several books, including Rival Magic, Nightingale, The Mirrorwood, A Game of Noctis, and The Delta Codex. She lives in Maine with her husband and their dog.
Returns
This item is eligible for free returns within 30 days of delivery. See our returns policy for further details.



