There are 1 book by Mark Nelson O'Brien on BookOrb. A strong starting point is Martin the Marlin (2019). The bibliography below is in publication order, with series grouped in reading order.
Standalone books
Frequently asked questions
How many books has Mark Nelson O'Brien written?
BookOrb lists 1 book by Mark Nelson O'Brien.
Where should I start with Mark Nelson O'Brien?
A good starting point is Martin the Marlin (2019).
What is the Mark Nelson O'Brien books in order list?
In publication order: 1. Martin the Marlin (2019).