Henry Reed is a young teen living overseas because his father is an American diplomat. His parents decide to send him to rural New Jersey to spend the summer with his aunt and uncle. Henry fears boredom, but within the space of the first few days, he adopts a stray beagle and meets Midge Glass, who becomes his friend and business partner during this and subsequent summers.
Henry and Midge attempt to start a research company using his uncle's old barn and stray animals acquired along the way, but in what is to become a recurrent theme across the series, roadblocks, most of them humorous, result in anything but a routine venture.
This book, and the subsequent books in the series, are well-written, vivid in their imagery, and brimming with facts hidden in the context of a well-told story. The subject matter is appropriate for pre-teens and teens and there is no objectionable material for parents to be concerned about.
This and subsequent books suffer from an unavoidable culture clash between the period the books were written (this first one was in 1959), and today's faced-paced, electronic environment. Pre-teens and teens will have no trouble with the themes and concepts in the story, but may need to look up some antiquated things (presumably not many teens in today's Princeton, New Jersey know what a sickle bar is).
Highly recommended, but with a caution on the cultural relevance to today's children.