Leather Care

I've had an interest in leather crafting for ages, I've never moved towards it however and I know very little about it. I have an uncle who works with leather, haven't seen him in years, he used to send us various leather items, mostly pouches and bags. I'm not sure what nubuck leather is, I'm sure he would know and know how to care for it, he probably sent us something made from it, I just never knew it.