The gist of this book is that the US is suffering from declining respect and financial and military strength, and that the world is beginning to suffer from overdue Malthusian shortages of critical resources. Because the US is in decline, the consequence will be international chaos as various actors (state and non-state, such as terrorists and international corporations) step into the void and inevitably begin to collide with the US and one another. The result of this will be global shortages of food, water and energy, increased protectionism, military conflagration, increased income disparity, and any other number of woes.
To support the inevitability of this dire future, Panzer cites Malthus, Paul Kennedy's book "The Rise and Fall of Great Powers," various fairly current news accounts, and less frequently, historic events. However, his rather strident argument of inevitable decline and collapse appears conclusory at best, and a critic might argue that the book itself represents a cynical attempt to capitalize upon the prevalent dour sentiments concerning the economy and America's position in the world.
Moreover, at times the tone of the book risks falling into condescending tongue clucking of the elite who, of course, saw this coming and are shocked, shocked, that we could ever allow this to happen. Take this quote from page 9, drawing parallels between the US and Rome as it was collapsing: "Instead of bread lines and circuses, we have NASCAR, video games and reality TV." 45 years ago, many Americans may have told you how the US was collapsing because of its softness in the face of communism, the Beatles, etc.
On the plus side, Panzner is well read, and he recounts a string of recent and several more remote historical events in great detail. My issue is not that he cites Malthus and Kennedy - it's that he comes up with quite specific predictions based upon a smattering of self-selected news and historical accounts. While the dire future he predicts may come into being, I'm not sure I agree that it WILL come to pass.
A second issue I take with this book is that it promises "cutting edge strategies and much needed direction that will allow you to achieve financial security and stability in an increasingly uncertain and dangerous world." I guess I missed this section other than some advice to invest in commodity producers. Moreover, given that the book essentially predicts a real-live "Road Warrior" world, I am skeptical whether any book could provide such "cutting edge" strategies, unless you consider building a bomb shelter and preparing for a survivalist future to be worthwhile.
On the plus side, the book is a fairly easy read, and the author has clearly spent much time combing the news media for information that appears to support his conclusions. Anyone wishing for a refresher about various international mishaps, primarily of the US, will find this book enjoyable.
Personally, I prefer Paul Kennedy's book "The Rise and Fall of Great Powers," which is truly a landmark book about the dangers of imperial over-reach. Another interesting, although not necessarily persuasive, read is Dent's "The Great Depression Ahead," which is distinguishable from "When Giants Fall" by its narrow focus upon demographics and provision of a bit more tangible financial planning advice.
In summary, I can't say that Panzner is wrong - his projections for the future might well be right. That being said, his book purports to predict the future with a certainty that does not appear supported by the data provided (keep in mind that the actual text of this book is slightly less than 190 pages, exclusive of the extensive bibliography). It is possible that Panzner sought to keep the book "readable," and hence cut down on the detail, but in this regard, I would have preferred to have more information supporting Panzner's conclusions, and some more hints about how to survive the collapse we are supposedly about to face.