I just finished this year and it's definitely a recommended read. We get a lot of stories about the night of the Wayne murders but this prequel book explores a rarely told part of the mythology: the last few days of Thomas and Martha's life.
I don't want to spoil too much but it really establishes the relationship between Alfred with both Thomas and Martha individually, the reason why he was hired to be their butler; to protect Bruce.
There's not much Jim Gordon, the key GCPD players are Harvey Bullock and Edward Nygma