There are 2 books by J. O'Callaghan on BookOrb. A strong starting point is Dual evolution (1921). The bibliography below is in publication order, with series grouped in reading order.
Standalone books
Frequently asked questions
How many books has J. O'Callaghan written?
BookOrb lists 2 books by J. O'Callaghan.
Where should I start with J. O'Callaghan?
A good starting point is Dual evolution (1921).
What is the J. O'Callaghan books in order list?
In publication order: 1. Dual evolution (1921), 2. Nomina Sacra Papyris Graecis Saeculi III Neotestamentariis (1970).