Here are samples of different ways contemporary script calligraphy can be integrated into book cover design. Most of these books are ongoing series, in which the hand lettered book title becomes part of the brand.
Casual, fun brush lettering integrated into the illustration
Monoline pen handwriting for Sophie Kinsella's "Shopaholic" series
Brush calligraphy that flows with the curves of the illustration
Script as illustration, a visual pun
Contemporary brush script designed to play off of a font
A long title treated as a text shape for Laurel House
Elegant contemporary pen calligraphy in two different styles