Best Shot is a series of art books/gameplay guides for some of the titles in the Dead or Alive series, which consist of Dead or Alive Xtreme Beach Volleyball, Dead or Alive Ultimate, Dead or Alive 4, and Dead or Alive Xtreme 2.
These books only provide basic gameplay guides, and doesn't give general tips on how to improve your skills. Also, during their print run, these books were only released in Japan, and therefore only avaliable; however, the guides are mostly in pictures so it's visually friendly for those who cannot read Japanese. Nevertheless, the books are primarily art books, with most of their content being renders and snapshots for the characters (mostly of the girls in the series). A few of them also included pull-out poster.
The books are now considered as collector's items, as they are no longer in print, and are no longer sold in major book stores. Secondhand and sealed copies can only be found in very few shops and most online stores. Online prices can vary from $15 to $40.