"The Great Great Wall" takes the reader back and forth between past and present as Ian Volner takes on man-made barriers throughout the ages through various prominent examples and contrasts them all with the events of today surrounding the major potential wall to-be, Donald Trump's US-Mexico border wall.

My big personal critique would be that by covering everything related to the proposed southern border wall in such detail right up until the (as of this review) relatively recent government shutdown, it makes the book feel that it's a little too of this very moment, and weakens its potential relevance as a result. However, to be fair to Volner he admits up front that the most prominent wall (or rather, wall-to-potentially-be) of our time is very much an ongoing event. Otherwise, "The Great Great Wall" overall does solid work covering the array of reasons and forces that haven driven people to erect walls over history. On top of that, the now-and-then contrast Volner structures the book around does indeed help provide a useful contextual lens for the present. And one specific theme from Volner's overview that stands out in particular that we should probably be wise enough to keep in mind - considering how the various empires and civilizations that built the major walls of history have long since crumbled, man-made barriers do not appear to be able to provide anything close to that long-lasting, cure-all protection that many believe them capable of.