There are 2 books by R. P. O'Brien on BookOrb. A strong starting point is Division of Space (2014). The bibliography below is in publication order, with series grouped in reading order.
Standalone books
Frequently asked questions
How many books has R. P. O'Brien written?
BookOrb lists 2 books by R. P. O'Brien.
Where should I start with R. P. O'Brien?
A good starting point is Division of Space (2014).
What is the R. P. O'Brien books in order list?
In publication order: 1. Division of Space (2014), 2. Year There Was No Winter (2017).