Don't think you have to be a student to study here, the doors are pretty open to everyone. This is one of my favorite spot to study or just read. Plenty of seats available in the late evening times. Best thing about this place too is there is a Coffee and Bean inside and a guest wifi available at the hours of 7-12 midnight, which is also the time it closes.
Parking can be very hectic if you don't have a student ID. If you're fit and don't mind the walk, you can park across Maryland Blvd. Lied Library is very clean and quiet. I like the fact that it's very well lit inside too, because it keeps me awake from getting bored from studying. A cool, quiet crowd as well that won't distract your reading. I'm sure there are plenty of resources and books but not really sure if that's open only to the students, since I bring my own books and materials when I come here to study.