Gr 5–8—Oversimplification, superficial coverage, and caricature-style illustrations limit the informational content and appeal of this set. Each volume covers more than 20 main topics—which receive about five paragraphs of text—as well as additional background chapters and grouped topics with single paragraphs about people or battles, all in less than 60 pages of main text. The diverse group of people, who include women and people from non-Western cultures who lived between ancient times and the space age, are given an overall "Hard as Nails" rating on a "Hardometer" scale of one to 10 that measures characteristics such as cunning, courage, and ruthlessness. There is no apparent organizational structure, which results in abrupt transitions, such as Ponce de Léon following Neil Armstrong, and some odd inclusions (e.g., space explorers are discussed in Travelers). VERDICT These books are unlikely to hold readers' attention and they will be of little value to middle school libraries.