A gripping book, The Declassification Engine: What History Reveals About America’s Top Secrets will appeal to anyone with a curiosity in American politics, government and archives as well as the declassification of any kind. However, the author can be subject to criticism on two specific aspects: First, the book is generally intriguing but gives the impression of being a mere accumulation of information. Likewise, it is evident that some sections include a significant amount of repetition. Furthermore, Connelly is highly concerned about the preservation of freedom of information. Nevertheless, there is one aspect that he struggles to acknowledge: certain material may be exceedingly sensitive to the extent that it does not serve the public’s interest for it to be released. Hence, classification is occasionally essential and it is unjust to completely denigrate it.