This is a series I completely missed as a kid, and I think, had I read them, I would not have been a fan. While my adult sensibilities love to read about clever pranks told in Henry's facetious tone, my younger self would have preferred more traditionally "girly" stories. This is why I think this book is a perfect choice for a reader who wants a real "boy story." Henry's voice as he writes his adventures in his journal is strongly masculine, and his summer adventures involve dirt, animals, tinkering, and goofing around in ways that are very boyish. As Beverly Cleary does in Strider, Keith Robertson really gets inside the mind of a young teenage boy and creates a believable and likable character.
Some things - particularly Robert McCloskey's illustrations and the utter lack of modern technology - date the book to the 1950s, but there is a Penderwicksian feeling of timelessness that transcends the time period and keeps the story feeling fresh and relevant even today. If you want to encourage skeptical young readers to pick up this book despite its age, emphasize the format (a diary just like Greg Heffley's!) and the sense of humor (think Gary Paulsen's Kevin Spencer.) Once readers are hooked, be prepared to also share the sequels to Henry Reed, Inc.: Henry Reed's Journey (1963), Henry Reed's Babysitting Service (1966), Henry Reed's Big Show (1970), and Henry Reed's Think Tank (1986).