The Glass Library
The Glass Library is a historical fantasy mystery series set in 1920s England. The books should be read in order. Although it's linked to the Glass and Steele series, you do not need to have read those books in order to enjoy The Glass Library.
The Medici Manuscript Book 2
The Untitled Books Book 3
The Dead Letter Delivery Book 4
Secrets of the Lost Ledgers Book 5