Gotham: Dawn of Darkness — Jason Starr

A break-in at Wayne Manor. The death of a masked intruder. Amid the seething crime and corruption of Gotham City, Thomas Wayne fights to protect his family and his company from forces unknown. While detective Harvey Bullock investigates the incident as a simple burglary, Wayne discovers that the threat may come from his own dark past. 

Peeling back layer upon layer of secrets, this is the official prequel to the hit television series.