When I think of boots, I think of jungle warfare. Call me crazy. But most books written about Vietnam seem to dedicate at least a little time talking about the havoc that having perpetually wet boots causes to your feet.
There's a million books about Vietnam war, but two I could recommend are The Things They Carried and Bloods: Black Veterans of the Vietnam War: An Oral History. They're very different, but both were very powerful. But you don't have to take my word for it!