This is book number 1 in the Ballpark Mysteries series.
"Folding information about Fenway Park and its colorful history into the tale, Kelly also artfully slips in simple red herrings along with real clues to the thief’s identity and the bat’s whereabouts that sharper readers may pick up before the young detectives do...Leading off a formulaic series that will take Mike and Kate to baseball parks around the major leagues, this book should draw baseball fans as well as budding whodunit aficionados." - Booklist
"A new series for emerging chapter-book readers combines the allure of baseball parks with the challenge of solving a mystery...Historical details about Fenway Park, including the secret code found on the manual scoreboard, a look at Wally the mascot and a peek into the gift shop, will keep the young baseball fan reading." - Kirkus Reviews
"Kelly throws in plenty of behind-the-scenes Fenway Park trivia (both in the story and in an appendix) and keeps the story moving at a quick pace, which should easily hold baseball-lovers' attention." - Publisher's Weekly
"...should score with the series chapter-book gang, particularly kids who enjoy the blend of fiction and information that keeps the Magic Tree House thriving. There are a couple of sly misdirections to please beginner mystery readers, some Fenway-specific trivia to intrigue nonfiction readers, and the promise of the entire gamut of major-league baseball stadiums yet to visit for those continuing with the series. A scattering of black-and-white pictures and appended “Dugout Notes” extend the fun." - The Bulletin of the Center for Children's Books
"...Any 6- 9 year old baseball fan would step to the plate and devour this book like a box of Crackerjacks! Kelly intersperses the perfect mix of sports action, crime-solving and facts about Fenway Park." - Examiner.com