Quill & Quire - November 1, 2014
"Flashy, quick and fun...A perfect Robert Ludlum-esque redux for the middle-grade set."
CanLit for Little Canadians blog - October 1, 2014
"What a great way to take readers from David McLean directing the actions of his grandsons, as he did in the Seven Series, to the boys looking to new adventures, pursuing their own suspicions and curiosity about their grandfather, and embarking on adventures that will put their intrepid natures to the test in more daring situations. Sleeper introduces the theme of espionage and hidden identities in an intriguing manner...[It] is a propitious beginning for my reading of The Seven Sequels. Make it one of yours too."
CM Magazine - September 5, 2014
"The setting is vibrant, and the thrills are a mile-a-minute. Fans of James Bond, Jason Bourne, and other action/espionage heroes will find much to love in Walters’ latest book for young readers. Highly Recommended."
School Library Journal - September 1, 2014
"This thrill-a-minute series will hook reluctant readers as well as fans of James Bond and Jason Bourne."
Kirkus Reviews - August 15, 2014
"Part Holmes-ian mystery and part James Bond adventure, DJ's quest requires both intellect and an unflappable resolve...[A] solid nod to the British spy and mystery legacy. A fast-paced, enjoyable entrée to this mystery/adventure series."
Hot Cup of Tea and a Good Book blog - July 5, 2014
"Sleeper will be the answer to all 'Which book should I read next?' questions this upcoming school year. It has something for everyone—strong male character, strong female character, mystery, spies, action, travel, fast cars, good role models, history and, yes, even a touch of a love story. Everyone should read Sleeper and when you read one, you'll be sure to read them all!"