All the Pretty Horses is the book preceding The Crossing in the trilogy. If you're going to read all of them, start with All the Pretty Horses. If you might not, read The Crossing. All the Pretty Horses is a magnificent story (made into one of the worst, most botched, poorly directed movies ever committed to celluloid, so don't let that stop you) of young courage, integrity and learning how the world really works. It is a top-flight masterpiece. Your life can not be complete without reading these two books.