OBNB doesn't sell books, but you may be able to find a copy at one of these websites:
Sraith pictiúr : scrúdú cainte na hArdteistiméireachta 2017 by Mícheál Ó Ruairc. ISBN 9781845366575. Published by Edco, AnComhlachtOideachais in 2015. Publication and catalogue information, links to buy online and reader comments.