Nevaeh is organizing textbooks on her bookshelf. She has a Spanish textbook, a math textbook, a history textbook, and a health textbook. How many different ways can she line the textbooks up on her bookshelf?

Nevaeh can line up the textbooks in 4! = 4 x 3 x 2 x 1 = <<4*3*2*1=24>>24 different ways. Answer: \boxed{24}.