THE IRISH…AND HOW THEY GOT THAT WAY, at the Mercury Theater. As commercial flag-wavers go, this musical revue is diverting and informative enough. But given Ireland’s rich literary tradition and turbulent history, one might have expected something better, especially since the script was penned by Frank McCourt, author of Angela’s Ashes. Instead this is a collection of 32 mostly familiar songs interspersed with occasionally poetic, melancholy reminiscences of Ireland and the Irish immigrant experience, performed by an able quintet of musical-theater performers and Susan Voelz, the estimable violinist of Poi Dog Pondering.

The best moments here are the most heart wrenching–first-person accounts of the potato famine, accompanied by the traditional song “Skibbereen,” and a stirring rendition of “Johnny I Hardly Knew Ye,” sung in memory of John F. Kennedy. But the show favors lightweight material, which is fine when it’s a rousing version of the Clancy Brothers’ “Finnegan’s Wake” but not when it’s an overlong tribute to George M. Cohan, featuring tired crowd pleasers like “You’re a Grand Old Flag” and “Give My Regards to Broadway.” A middle-of-the-road show like this one cries out for the fervor of W.B. Yeats, the mad brilliance of James Joyce, or the antiestablishment fury of the Pogues. But the closest it comes to contemporary material is a sappy show-tune version of U2’s “I Still Haven’t Found What I’m Looking For.” It doesn’t even approach the passion of the Van Morrison and Chieftains music played during intermission.

–Adam Langer