There are 2 books by Kelly O'Callan on BookOrb. A strong starting point is Cardholder (2013). The bibliography below is in publication order, with series grouped in reading order.
Standalone books
Frequently asked questions
How many books has Kelly O'Callan written?
BookOrb lists 2 books by Kelly O'Callan.
Where should I start with Kelly O'Callan?
A good starting point is Cardholder (2013).
What is the Kelly O'Callan books in order list?
In publication order: 1. Cardholder (2013), 2. Breaking Limbo (2013).