Throne of Glass is a young adult fantasy novel series written by Sarah J. Maas. It follows the journey of a young assassin named Celaena Sardothien as she navigates the treacherous world of the kingdom of Adarlan and fights to reclaim her throne as the rightful queen.
Augustea Open is most likely the font used for the book title in the cover. It's an all-capital inscribed font designed by Alessandro Butti and Aldo Novarese. This font is based on the traditional Capitalis proportions, which were prevalent in the first century AD during Augustus' era. The balanced, regal, and classic appearance of Augustea sets it apart.