If the first week of South Pacific rehearsals had a figurative feel of going back to school, then the second week has been a more literal demonstration of the classroom. Amidst all the scene analysis and the dance and movement work the cast is getting a short course in the Second World War as it was fought against the Japanese: today, professional historians spoke at rehearsal; and, this Sunday, World War II veterans will speak to the group.

Specifics from those appearances - what the experts said, comments from the cast - will show up in future blog postings. For the moment, though, I want to mention the person who has for many weeks been organizing all the historical materials which everyone has been using to familiarize themselves with the time period. This is a crucial role: no one in the vast cast had even been born in the early to mid-1940s, when South Pacific takes place, so providing context is crucial. The person I'm speaking of -- the project's unofficial on-site historian -- is assistant director, Sarna Lapine.

Lapine worked with South Pacific director Bartlett Sher on the Lincoln Center Theater productions of Awake and Sing and The Light in the Piazza. "For the current assignment," Lapine says, "I spent four days in Washington doing research primarily at the Naval Historical Society. I talked to people from the Marine Armory in Brooklyn, who've helped us find people to help instruct the cast in things like how to handle a weapon." The results of all this scholarly digging include Lapine's assemblage of the rehearsal room's impressive wall of text and photos from the Pacific campaign: some of this material is practical ("A Day in the Life of a Seabee") and some is deadly serious ("The Battle of Guadalcanal").

Lapine's research has also had a personal aspect. "My brother, Seth Lapine," she says, "is a Major in the Marine Corps. He's served in Iraq. I had him read the script of South Pacific, and we spent time discussing it in some detail. In many ways, he's been the most valuable resource I had as I went about trying to help everybody understand what it's like to be in the Navy -- an organization with so many rules and regulations." She added, laughing: "That's nothing like a rehearsal room, of course!

BRENDAN LEMON is the American theater critic for the Financial Timesand the editor of lemonwade.com.