The Count of Monte Cristo
This book is good for many reasons but I'm enjoying spending time in this world where communication isn't instant, photographs aren't invented, and people seem to take their honor very seriously.
I also learned that the telegraph used to be semaphore-like flags that were relayed along sight lines, and only replaced by Morse code much later.
https://en.wikipedia.org/wiki/Optical_telegraph
This book speaks to me as a trans person
The Black Count