Wolf spiders are large spiders, often striped, that are typically seen on the ground or, if indoors, on the floor. They do not spin webs. Instead they sometimes run down their prey, like wolves, or wait in ambush near the mouth of a burrow.
With eight eyes arranged in three rows, they have excellent eyesight. They are solitary arthropods, except that the female carries fertilized eggs with her. Once the spiderlings hatch, they crowd onto their mother’s abdomen, where they stay for several weeks until they can live on their own.
The large spider running across the floor that you see while reading at 3 am is probably a wolf spider, as they hunt at night, move very quickly, and can live in houses. The best thing you can do is to leave it alone. It will eat insects like crickets and cockroaches.