| Spoiler Warning!|
This article contains major spoilers.
Reader discretion is advised.
|“||What if your whole world was a lie? What if a single revelation—like a single choice—changed everything? What if love and loyalty made you do things you never expected?||”|
|One choice will define you.|
|Publication date||October 22, 2013|
The faction-based society that Tris Prior once believed in is shattered—fractured by violence and power struggles and scarred by loss and betrayal. So when offered a chance to explore the world past the limits she's known, Tris is ready. Perhaps beyond the fence, she and Tobias will find a simple new life together, free from complicated lies, tangled loyalties, and painful memories.
But Tris's new reality is even more alarming than the one she left behind. Old discoveries are quickly rendered meaningless. Explosive new truths change the hearts of those she loves. And once again, Tris must battle to comprehend the complexities of human nature—and of herself—while facing impossible choices about courage, allegiance, sacrifice, and love.
- There were several titles rumored for this book, speculation based on the "-gent" theme of the previous titles. Among the more popular fan-guessed titles were also used on the reveal video: Convergent, Emergent, Resurgent, and even Detergent, which the fans and Veronica Roth has been using to refer to the third book as a joke.
- The cover was officially revealed on May 9th, 2013.
- The definition of Allegiant is loyal or steadfast in devotion (especially to a government).
- The catchphrase will be "One choice will define you."
- The symbol on the cover isn't a faction symbol like its predecessors, but the symbol will make an appearance in the book. 
- To Veronica Roth, the term allegiant means "one who is loyal or faithful to a particular cause or person" 
- At the 2013 San Diego ComicCon panel, Veronica Roth revealed that Allegiant will be written in dual perspectives -- Tris and Four will be the narrators for the third and final installment.