Reviews of the book were overwhelmingly positive. In a starred review, Booklist says that "Sheinkin offers a fascinating portrait" of Ellsberg. They add that it is both "thorough and challenging" and "powerful and thought-provoking. " Publishers Weekly starts off its starred review by saying that "Sheinkin. . . has done again what he does so well: condense mountains of research into a concise, accessible, and riveting account of history," that "read[s] like the stuff of spy novels and will keep readers racing forward. " A starred Kirkus Reviews review calls it "Lively, detailed" and "fully documented" before proclaiming the book to be "Easily the best study of the Vietnam War available for teen readers. " Its fourth starred review, given by VOYA, calls it "Fast-paced and fascinating" and "backed up by meticulous research. " Another starred review was handed out by School Library Journal, stating that the book is "Thoroughly researched. . . and beautifully written. " The Horn Book slaps down a sixth star, and says the book is so good, Sheinkin "has outdone even himself. " The stars continue with one from Bulletin of the Center for Children's Books, which calls Most Dangerous a "thrilling ride. " The Washington Post declined to give a star, but did inform their readers that Most Dangerous is "Sheinkin's most compelling yet. " The New York Times followed suit in the lack of a star, but did call the book "gripping". It then noted that "the author has a perfect ear for what might hold the attention of young readers" and it will "help them understand" why the world has become a place of "endless war and all-pervasive surveillance is a matter of course. "
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