(2) 4-6 Illustrated by Manu Montoya. In this installment Reynie, Sticky, and Kate are now teens, and cranky telepathic genius Constance is almost a tween. The henchmen of Mr. Curtain escape from prison and plan to free their boss from the maximum-security KEEP, but Mr. Curtain has poisoned Mr. Benedict, the children's mentor, to force the Society to attempt a rescue. It's a puzzle-lover's extravaganza, with codes, riddles, and clues to solve and security measures to be finessed.

Reviewer: Anita L. Burkam | Horn Book Magazine Issue: September, 2019

(2) 4-6 Reuben Pedley discovers an antique pocket watch with the power to turn the bearer invisible. As Reuben seeks the history of the watch and why villain The Smoke is so desperate to get his hands on it, the plot builds with a clean, comprehensible line that makes the over-five-hundred pages read effortlessly. Black-and-white illustrations lend a slightly gloomy, timeworn air.

Reviewer: Anita L. Burkam | Horn Book Magazine Issue: July, 2016

(2) 4-6 Nicholas Benedict is the brilliant narcoleptic mentor of the eccentric, puzzle-loving Mysterious Benedict Society. In this story from his childhood, nine-year-old orphan Nicholas discovers a mystery but also a gang of bullies. The mystery drives the plot, the bullies add tension, and Nicholas's emotional development deepens the tenderness. Fans will be pleased with the entirely earned, feel-good ending they expect from Stewart.

Reviewer: Anita L. Burkam | Horn Book Magazine Issue: March, 2012

(3) 4-6 Illustrated by Diana Sudyka. Profiles of the Society's members, pull-quotes, "archival material," and page after page of Benedict Society–themed brainteasers mingle in this challenging but rewarding volume. Red circles on nearly every page contain clues to a final puzzle, and a hint section in the back will nudge strugglers. Sudyka's copious illustrations add a quirky flavor.

Reviewer: Anita L. Burkam

(2) 4-6 Illustrated by Diana Sudyka. The members of the Mysterious Benedict Society have been sequestered to keep their nemesis from capturing them. When the children fall into a trap, they must bring all their skills (including Constance's burgeoning telepathic powers) to bear. As in the previous series entries, the children's well-delineated characters are believable, and the narrative puzzles mesh with thumping good action scenes.

Reviewer: Anita L. Burkam | Horn Book Magazine Issue: November, 2009

(2) 4-6 Illustrated by Diana Sudyka. When Mr. Benedict is kidnapped, the four gifted members of the Mysterious Benedict Society must solve a puzzle-quest to rescue him, their footsteps dogged by creepy henchmen. Stewart keeps interest high with first-rate brainteasers, physical danger, and the children's own complex dynamics. Readers charmed by the first book's plot twists and quirky details will find this a worthy successor.

Reviewer: Anita L. Burkam | Horn Book Magazine Issue: May, 2008

(2) 4-6 Illustrated by Carson Ellis. Orphan Reynie Muldoon becomes a member of a crack team tasked to infiltrate the Learning Institute for the Very Enlightened. Their job: to discover the purpose behind subliminal messages emitted from the school. The children face danger and discovery, puzzles and plots, and their own mortal weaknesses. With its lively style, fresh character portrayals, and well-timed revelations, this story flies along.

Reviewer: Anita L. Burkam | Horn Book Magazine Issue: March, 2007