The publishers of this series, "The Unexplained," indulge in some exaggeration when they say that the books "explain the science behind mysterious events and tell the stories behind unexplained occurrences." Much of the so-called evidence is anecdotal, unverifiable, and presented without documentation. Each book is divided into four chapters: explaining the mystery, relating some history of belief in it, describing investigations, and summing up the evidence. Since the 1970s, mysterious circles of crushed stems have appeared in farm fields (usually wheat, barley, or oats) primarily in southern England. Some are very elaborate designs in combinations of patterns. Crop circles are more fascinating than most strange occurrences because they leave visible imprints that can be analyzed. Scientists believe they may be caused by whirlwinds or ball lightning; two Englishmen have claimed they created 250 of them, though there is no real proof. Still, some remain unexplained—could aliens have made them? The publishers state they are aiming to capture the attention of reluctant readers with the exoticism of the subject matter, a controlled vocabulary, short sentences, and an uncluttered format. While middle readers may be intrigued by these mysteries in spite of the uninspired writing, it is equally important that teachers and parents make sure students realize that a scientific investigation depends on verifiable proof and that a report on research must be fully documented to be taken seriously. This title on crop circles is the most interesting and satisfyingly informative book in the series.