I gained access to the book through oxford scholarship online who accepted my open university passwords (saying this cos I need to acknowledge my internet provider resource) and it is interesting that Thomas Robinson disagrees with Rodney Stark's thesis that Christianity was an urban development during the first 350 years of its existence. A main argument is that the city and the country were fairly fluidly connected and that, moreover, the middle classes who were so attracted to Christianity were present also in the countryside and as that was the case they would have carried the christian message to them.
Another line he takes up is based on the presence of country bishops called chorepiscopoi who were of the same rank as city bishops and had full voting rights like city bishops. Such chorepisicopoi must already have been in existence, he argues as some of them attended the council of Anchyra in 314 CE and participated in the council. chora translates as country and piscopoi translates as bishop. i think this is quite a strong line of argument against those who claim that countryside christianity did not develop until the latter half of the third century (p. 199).
Basically Robinson is keen to re-open this debate and feels that our understanding would be enriched if more attention was given to how Christianity developed amongst country folk. He argues that such virtues as charity towards less sophisticated folk makes more sense if we factor in the countryside.
Another important point that I found interesting is that he argues that there were far more gentile converts than Jewish converts to Christianity than some scholars are willing to admit.