Mark Zwonitzer is a writer-director whose work appears nationally on public television. He is currently finishing up work on a documentary about the creation of the transcontinental railroad and plans soon to begin work on a documentry about the Carter Family. Charles Hirshberg, a writer at Popular Science magazine, is the author of Elvis (Warner Books) and The Beatles (Little, Brown). Prior to joining Popular Science, he worked at Life magazine, and before that was a staff writer at The Los Angeles Times and The Washington Post Magazine.