David Harrower's Blackbird is what I call a special-problem play. Unlike the 19th- century "problem plays" in which characters embodied different positions on a then current issue, plays of this kind exploit the issue by positing a special case hedged around with extenuating circumstances and elaborately contrived mishaps till the issue itself loses all resonance. Yes, it was child abuse, but she led him on, and he really loved her, and it would all have been different if he'd come back to the hotel room sooner, and besides he already did time for it, so why is she bothering him now? Maybe you'll care; I couldn't. Despite Jeff Daniels's and Alison Pill's excellent efforts, all I kept wondering was why director Joe Mantello had the set revolve for no reason.