If you want to print high resolution book cover, consider whether you want to print on one side only or double side. If you intend to print on one side, you just need to buy common single side photo paper. But if you want to print on both side, you need to buy "double side matte paper". This kind of paper is usually used for book cover, or for box-making purpose.
Usually Matte Paper is not glossy. So, if you want to have double sided glossy printing, you'll have to buy double side photo paper.
But if you just intend to print double-sided, but one side with glossy and another side with text only, you can just buy single side photo paper BUT make sure that the unglossy side is not smooth, because you can't print on smooth side (I mean uncoated smooth side).
Usually branded single side photo paper can't be use to print on the back side EVEN with text only!
This is because most ordinary inkjet printer ink will be smeared on the smooth back side (I've ever tried on Fuji Photo Paper with refill ink).
So, just buy a pack of photo paper and test. Nothing is better than to experience it yourself.