The book sounds like a worthwhile read – thanks for posting, Mike. Freedom of movement is indeed a lot like free markets in general, in that it's difficult to readily understand how much of a difference these things make in terms of prosperity. How many people understand that world productivity could double with open borders, and what that would mean in terms of improvement in people's lives?
A good related piece from FEE describes the history of passports, the use of which began as a temporary war measure in 1914. As recently as 1963, there were international discussions about getting rid of them and restoring the freedom they eliminated. But now most people take them for granted, showing once again that once governments have been allowed new powers to restrict freedom, these can be difficult to reverse:
https://fee.org/articles/passports-were-a-temporary-war-measure/
Love & Liberty,
((( starchild )))