Here, this might not be the first book I'd recommend, but it's widely available to read for free and while I think the general lack of a detailed class analysis hurts Paxton's work, he is still the guy who was warning in the 90's that fascism existed, and could quite easily be a threat in the Pig Empire West going forward.
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://files.libcom.org/files/Robert%20O.%20Paxton-The%20Anatomy%20of%20Fascism%20%20-Knopf%20%282004%29.pdf
PS - it took him a while to come around, but eventually Paxton did say Trump was a fascist.