Continuing the adventures of intrepid Martin Moone begun in the first book, Moone Boy, this title follows Martin and his invisible friend Sean Murphy as they get into even more trouble. Martin desperately wants a Game Boy for Christmas, but since times are tough, his parents cannot afford one. In fact, they even make every family member responsible for some part of the holiday festivities, including finding a Christmas tree. After failing at several jobs, Martin finally finds a job as a butcher's boy, but he's not very good at what he does. His employer, the curmudgeonly Bridget Cross, enlists his services in spying on her competitor, Francie Feeley. To his surprise, he discovers the secret to Francie's success, and everything turns out just fine for everyone except Bridget. But that doesn't happen without a few hiccups and a betrayal from Padraic, Martin's best friend. The book is humorous, especially with its asides and references to Irish terms or foods. But even though middle grade readers will be amused--yes, it has that sort of humor--it does tackle some current issues concerning xenophobia and immigration in a thoughtful fashion. I guarantee you've never read a spy book quite like this one. The book was originally published in Great Britain, giving fans of that particular sort of humor a chance to bask in it while providing an introduction to what might be considered humorous in another country.