For my money (not a lot tbh) she's one of the best filmmakers working today. Her movies are lyrical but never sentimental, morally serious but never self-righteous. She is especially interested in themes about the body, desire, colonialism. My favourites are Beau Travail, Trouble Every Day, and White Material.
Claire Denis is the best living director😌
Kelly Reichardt (fav current american director) and Lucrecia Martel are also two of the best around.
I recommend their entire filmographies, but here are some starting points for all 3:
Claire Denis - Beau Travail, White Material, 35 Shots of Rum Kelly Reichardt - Wendy and Lucy, Certain Women, Meek’s Cutoff Lucrecia Martel - La ciénaga, Zama, The Headless Woman
A lot of the stuff that gets recommended for beginners actually sucks, imo. If you want to get an idea of what it's about, try these:
Edmund Wilson, To the Finland Station
Andrew Collier, Marx: A Beginner's Guide
Michael Heinrich, An Introduction to the Three Volumes of Karl Marx's Capital
C.L.R. James, Modern Politics
Science fiction space opera with a mordant sense of humour, set in a far future Fully Automated Space Communism type setting. Like a gritter and sexier Star Trek, but in a good way.