Minimalistic book covers
There's something about minimalistic book covers that just looks so cool and stylish. They make books seem more sophisticated and "serious", which is why a lot of people are drawn to them.
Interestingly, minimalistic book covers often convey more information than their more busy counterparts. Because there's less going on, the few elements that are present become that much more important, and thus convey more meaning.
You might also enjoy Negative Space Book Covers and Orange Book Covers