I know your question was put to Dr. Jewell, but I happened to write a research paper on the Irish Troubles in college and several books were indispensable to my research that I’d highly recommend. Dr. Jewell may have other works in mind, but I thought I’d share mine as well.
The Origins of the Present Troubles in Northern Ireland.
Making Sense of the Troubles: The Story of the Conflict in Northern Ireland.
The Course of Irish History
P.S. I also asked Professor Casey about his take on the Troubles during the last live QA session (at around 33 minutes into it) if you’re interested in hearing his assessment of it.