Here's a great interview Ken Levine did with Chip Zien in Levine's podcast. Levine is a TV comedy writer (MASH, Cheers, Frazier, etc.) and a playwright. He and Zien worked together on an earlier TV show but this interview is filled with great stories about Zien's experience working with Sondheim, Lapine, etc. I think Alan Scott once said Sondheim has a repertoire of interview answers and he sticks to them pretty closely. Zien offers some of the same stories (e.g., neighbor Katherine Hepburn) from a different perspective. Also, great ITW stories. Enjoy.