Like many people here, I read this book for a college class concerned with providing an explanation of the numerous questions that arise whenever one ponders America in Vietnam, like why it was there, and why it lost. Any student or curious reader should find this work a great tool for this task.
The book is fairly short, numbering less than 400 pages. By that restraint alone, no reader should expect a thorough, voluminous exposition on every aspect of the war akin to Rise and Fall of the Roman Empire, or a textbook for that matter. It's a piece on political history with a general thesis, numerous recurring themes, and plenty of information to back everything up.
The thesis is that the containment strategy America adopted around the Korean War, and its perceiving Vietnam as a strategic door to all of Southeast Asia, prevented each successive president from leaving Vietnam to the wolves and forced each one to progressively raise American stakes n the region. Numerous other variables--some consistent to all presidencies, like fear of facing the same political bloodletting as Truman got over "losing" China in 1949; some specific to the president, like JFK's need to take a stand somewhere after negotiating on Laos, and after the Berlin wall was erected--accompanied this grand one, but the central theme of this book draws a vivid picture of proud Cold Warriors refusing to back down and unwilling to commit entirely, hoping to bluff out an enemy who had already gone all in.
Of course, because it is a work with a point to prove rather than a huge collection of unfiltered facts, the reader must be wary of buying into Herring's perspective without private review of his logic. That's true for every book of this sort, however, and for what it's worth, Herring makes a very convincing case.
On the technical side of things, this book could have done more to centralize its presentation of thematic events. Since the author shifts between historical narrative and analysis, the latter could have summaries and reminders of recurring concepts on the margins. As it is, the reader has to discover themes like "US arrogance" or "governmental deception" by himself and note their recurrence without any assistance from Herring. Doing this isn't the standard for most books, though (the only one I can think off that does this is Landmark Thucydides), I can't criticize the book for not following up on these suggestions.