Transatlantic is a beautifully composed book, one that I feel like I didn't devote my full attention to (I sometimes read too many books at once, and one inevitably gets neglected) and should read again.
In this sweeping narrative, McCann weaves together intergenerational and intercontinental relationships. The novel jumps around chronologically, from Frederick Douglass' visit to Ireland in 1845, to the present, illustrating how decisions, chance occurrences, and conflict (namely the violence in Northern Ireland, but also the American Civil War and WWI) resonate through the generations. At the center of the novel is Lily Duggan and her lineage, creating a history that stretches between Britain and North America.
I do feel the book lags a little during the chapter about the US senator and the peace negotiations in Northern Ireland during the 1990s. The book is somewhat slow in general, but this chapter drags its feet, somewhat appropriately mirroring the age and exhaustion of its central character and the negotiation process itself. I almost think this chapter could have been excluded because it strays a little from the family's story, but I understand it's inclusion. Maybe it could have been shorter, though.
Aside from that small issue, this is a really lovely book. The story, across the generations, is twinged with nostalgia and melancholy, without being overly sentimental. McCann writes with a focus on language rather than plot, so if you are looking for lyricism and poetry in prose, I highly recommend this elegant novel.