Footsteps, footsteps, footsteps...

I seem to always be talking about footsteps in my ghost lectures, but it actually seems that this is the most common occurrence of anything else. I tend to always hear things before I see or feel something. The last time that it happened was just a few minutes before wiriting this, when I heard steps in the center stairwell of our 1861 home. There was no one there - at least, no one that I could see...