A lot of Irish records ( particularly Ulster ones) were destroyed in a fire. Progress is difficult unless you have specific parish / church references.
A useful source of information can be via Rootschat. There are a lot of keen genealogists on there, who will generally be able to come up with suggestions - some of which may seem a bit 'off the wall' yet have helped me a lot. Simple things like census enumerators writing down what they think they've heard, when dealing with illiterate people. I 'lost' my ancestors in one census - only to find them when Stark ( spoken with a strong Fife accent) became transcribed as Steark.
Other sources are via records held by the LDS church - and are available for free. Also try the International Genealogical Index - (IGI), and Rootsweb, and familysearch.org.
There are also a number of 'one name studies' -- Try a search using 'Boylan one name study'.
That should keep you going for several months! -- This game can be a proverbial 'black hole for time'.
If you have no luck with the above very good suggestions, I can recommend visiting the last place showing records for your ancestor. At the very least, you'd have a lovely mini-break in Ireland!
Its true that lots of Irish records got destroyed in the Irish civil war when the Post Office on O'Connell Street in Dublin was damaged. However, Ireland is a very small country and the rural areas in particular have tiny populations.
I went to find a village that no longer existed in County Mayo, where my Grandfather was born. The parish church didn't hold many old records but it did have a rough illustration of the area circa the correct time. I talked to some people around the buildings that fitted the last census address and the local library was a great help too in finding out about the history of the area.
I eventually found the old family cottage (now used to store farm implements!) and brought back an old bottle from the site, plus lots of pictures. Next I need to go to Donegal and repeat the process, which will be fun as well!