Template:Book cover image
This is a special case of "fair use" for book covers, there are no parameters as the fair use criteria are already filled in. Fair Use allows the use of book covers for review purposes quite readily.
If the image is to be used to illustrate an article other than the one about the book itself, it is important to obtain copyright or fill in an additional fair use rationale.
If the book cover is in the public domain, use the PD copyright notice instead, the image can then be used freely.