I really like the UK's The Book Depository for finding books to buy.
Advanced book search at The Book Depository
I did a search on R.B. Conroy.
I mainly use the Book Depository for Simon Scarrow books. These are kind of hard to find in libraries in the US because he is a UK writer who writes about the adventures of a pair of 1st Century AD Roman legionnaires Macro and Cato.
http://en.wikipedia.org/wiki/Eagle_Series