Ash and Quill by Rachel Caine
My rating: 4.5 of 5 stars.
Series: The Great Library (Book 3 of 5)
Genre: Young adult, alternate history, historical fantasy, fantasy
Published: July 2017 by Berkley Books (US) and Allison & Busby (UK)
Immensely engaging and intense, Ash and Quill was mid-series perfection.