There are 1 book by W.J. O'Brien on BookOrb. A strong starting point is This Day's Business (2005). The bibliography below is in publication order, with series grouped in reading order.
Standalone books
Frequently asked questions
How many books has W.J. O'Brien written?
BookOrb lists 1 book by W.J. O'Brien.
Where should I start with W.J. O'Brien?
A good starting point is This Day's Business (2005).
What is the W.J. O'Brien books in order list?
In publication order: 1. This Day's Business (2005).