Sorry you couldn't make it. You really should take Nate's advice.
The focus as noted in the OP, was on Mr. Shiels' new book,
The Forgotten Irish, focusing on the experience of about 30 immigrant families whose sons, husbands, fathers and brothers fought with the Union Army. Interestingly (and unexpectedly), Shiels was joined by Dr. David Gleeson, a native of Ireland who did graduate work in the U.S. and taught for some years at the College of Charleston in South Carolina. Gleeson is currently a professor of American History at Northumbria University, Newcastle upon Tyne in England. He is an expert on Irish immigrants in the 19th century South.
The turnout for these gentlemen was about 100 people (across the age spectrum), not too shabby for a bitter winter's evening.
I learned a lot and was taken aback by Mr. Shiels' assertion that surviving Union Army pension application records are probably the deepest and richest source of Ireland's social 19th century history that exists, anywhere. He explained that records in Ireland itself were not well protected, if kept at all and sometimes purposefully destroyed. One hundred eighty thousand Irish-born men served in the Union Army and the correspondence, affidavits, etc., that they, their wives, parents and dependent children provided to pension authorities survive. It is on these records his book is based and I look forward to reading it.
Happy St. Patrick's Day!