Victoria Schwab writes powerful fantasy, both for young adults and adults (the latter as V.E. Schwab). The Shades of Magic series, with its magical parallel Londons, and the magician Kell and pirate/thief Delilah Bard protagonists, is excellent. And I like even more the Archived series, with its uncanny library of dead people.
Schwab is touring the UK from 28 July to 5 August; details here.
