Theater rarely generates raves like this, but the superlatives come springing off the page in Ben Brantley's review of "The Seagull." Brantley crows that Ian Rickson's staging is "the finest and most fully involving production of Chekhov that I have ever known." Chekhov's classic ensemble play takes theater itself as its subject, exploring the relationships between its four artistic leads. Big names like Kristin Scott Thomas and Peter Saarsgard strut their stuff on stage, but their individual talents hardly distract from the play's "society of equals," which "turns loneliness and restlessness into a stuttering pyrotechnic display." "The Seagull" runs on Broadway through December 21.