There are 1 book by Roger T. O'Callaghan on BookOrb. A strong starting point is Aram Naharaim (1948). The bibliography below is in publication order, with series grouped in reading order.
Standalone books
Frequently asked questions
How many books has Roger T. O'Callaghan written?
BookOrb lists 1 book by Roger T. O'Callaghan.
Where should I start with Roger T. O'Callaghan?
A good starting point is Aram Naharaim (1948).
What is the Roger T. O'Callaghan books in order list?
In publication order: 1. Aram Naharaim (1948).