That's an overwhelmingly broad topic. I might suggest you narrow it down to the historiography of a single case study. I feel like I could write a book on the historiography of a single general. Examining the entire Civil War would require years of research (and still be fairly cursory).

I think your best bet is to read the foreword or introduction of a variety of books. That's often the location that authors will summarize past research on their chosen topic.

Good luck!