All Maze Runner books by James Dashner — all 5 books in publication order, including the two prequels.
Thomas wakes up in a glade with no memories, surrounded by other boys, and a vast maze. Every night the maze's walls close, trapping horrific creatures called Grievers inside. The series delivers relentless momentum and a mystery that keeps compounding through 5 books. The films starring Dylan O'Brien brought the series to a massive new audience, though the books go further and darker than the adaptations.
Start with The Maze Runner (2009) — the original and best.
Thomas arrives in the Glade with no memory, surrounded by a community of boys trapped inside a giant maze. The walls move. The monsters come at night. Someone has to figure out a way out.
Escape from the maze was only the beginning. Thomas and the Gladers face a new, even more dangerous trial across a scorched wasteland. WICKED is still running the show.
The final chapter. Thomas must fight WICKED to the end — and the truth about the trials is more disturbing than anyone expected. The conclusion of the main trilogy.
Set before Thomas entered the maze, this prequel follows Mark and Trina as they survive the sun flares that destroyed civilization and the beginning of the Flare plague. Best read after the main trilogy.
The final prequel — how WICKED built the maze and how Thomas and the other Gladers were recruited. Fills in crucial backstory and is the best of the two prequels for main-trilogy fans.
Publication order: The Maze Runner, The Scorch Trials, The Death Cure, then the prequels The Kill Order and The Fever Code. The main trilogy must be read in sequence.
They're optional but worthwhile if you want more of the world. The Fever Code is the better of the two — it fills in how the maze was built and how Thomas ended up there. The Kill Order follows different characters and is more of a post-apocalyptic survival story.
Publication order is strongly recommended for first-time readers. The prequels make much more sense and have greater emotional impact if you already know how the main trilogy ends. Chronological order (prequels first) spoils key mysteries in the main trilogy.