“It Can’t Happen Here” by Lewis Sinclair. – http://gutenberg.net.au/ebooks03/0301001h.html
“American Fascists: The Christian Right and the War On America” by Chris Hedges (Not on Gutenberg).
“Empire of Illusion: The End of Literacy and the Triumph of Spectacle” by Chris Hedges (Not on Gutenberg).
All good choices to start with.