Why on earth was Chancellor Palpatine so obsessed with the Skywalkers?

I’ve only seen the first six Star Wars films; there are still more movies for me to watch and lore for me to grasp. But there’s one thing I don’t get: why the hell was Chancellor Palpatine so obsessed with Skywalker—with wanting to control him, I mean, and turn him to the dark side? Why was he so obsessed?