Gr 4–6—While the content is centered on early U.S. history, the emphasis here is on historical analysis. Lessons are repeated throughout the series, especially the distinction between primary and secondary sources and identification of bias. The volume weighing the causes of the Civil War is especially incisive in its treatment of competing claims about states' rights and motivations for secession. Page sections are set off throughout the series to stress definitions of key terms and concepts, as well as to encourage forceful questioning. For example, readers are asked to consider how the same person might be called a traitor in loyalist literature and a patriot by American revolutionaries. Illustrations too often are bland stock photos, but many maps and historical portraits and engravings are included. A link is provided for a curated list of online resources, but otherwise references are not provided. VERDICT Despite some shortcomings, a much-needed boost for critical thinking.