Unpopular non-fiction book that you think everyone should read

Hi everyone! Over the past three years, my interest in non-fiction books and docu-series has really taken off, and I want to dive deeper and expand my knowledge. Could you recommend a book that may not be widely recognized or popular, yet you believe is essential and everyone should read it? It might be a hidden gem, or perhaps it covers a niche subject that’s not widely known. Anything goes, as long as it’s non-fiction. Thanks!

by Oueiles