What is a good book to study linear algebra?

"Linear Algebra Done Right" by Sheldon Axler is an excellent book.

Gilbert Strang has a ton of resources on his webpage, most of which are quite good:

http://www-math.mit.edu/~gs/

Well, I will just add a few online resources that I have used before,

1. William Chen's Lecture Notes
2. Jim Hefferon's Linear Algebra
3. Edwin Connell's Linear Algebra
4. Keith Matthew's Linear Algebra
5. Keith Matthew's Lecture Notes on some advanced linear algebra
6. Ruslan Sharipov's Course of linear algebra and multidimensional geometry