Rosalind Krauss is an influential art critic and theorist. Her career started in the mid 60's and continues today. She was especially important in the advancement of the Post Modern movement.
Early in her career, Krauss worked with the art critic Clement Greenberg who is considered a formalist. He preferred artwork that embraces its formal elements and advances its art medium. Krauss on the other hand also believes in the importance of art medium but believes that anything can become art. If the artist works with it enough to make it itself an art medium. The medium becomes the "rules" of the piece.
The theory of "expanded field" can be credited to her, and she was influential in her use of tables for explaining her concepts.
Her most recent book Under the Blue Cup talks about her recovery from a brain aneurysm and how the experience influenced her theories on art. "Brain-the medium is the memory."
Here and here are interviews with her, and below is a quick video. She has a lot of interesting ideas on discussing elements of art. However, I felt there's so much in her work it's hard to digest it all. I know I'll be re-reading her book and those interviews a few more times. I recommend you check out her books too, but to start this website has a clear explanation of her theories.
A few of her ideas that really captured my attention include her critique on the white cube and installation art (because I've witnessed ineffective installation art in galleries), and her discussion on memory. That's a concept I've been eager to explore in my own artwork.
Below is a statement by her on reading art that I think is a good way for all of us to approach artwork.
"...what I’m more interested in is stumbling on work that for one reason or another I recognize as genuine and then I try to understand where it comes from and what it is that secures the notion of it as authentic."