These colorful volumes from the ongoing Mystery Files series briefly present particular facets of high-interest subjects. Following the introduction to the broad topic, each book offers a dozen double-page presentations designed to intrigue readers. Lost Treasures looks at El Dorado, the Lost Dutchman's Mine in the Superstition Mountains, and a hoard of Roman silver coins found in England in 1999. Each two-page section includes a few paragraphs of text, a short sidebar and at least two illustrations, often photos and/or period illustrations. Given the books' brevity and the broad scope of their subjects, it's not surprising that the content in each section is scanty. Still, readers interested in individual topics may be motivated to look elsewhere for more detailed information. Good supplementary materials for larger collections.