The National Yiddish Book Center is trying to double the size of its Amherst, Mass. facility. The center, which has the largest collection of Yiddish literature in the world, was founded in 1980. Its staff would like to turn the library into a Yiddish academy with shelf space for a half-million books, center officials said in a release. The academy also would have classrooms, seminar rooms, a performance hall, a kosher kitchen and an outdoor tent that could seat 600 people for performances. The center has started a $6 million capital campaign to pay for the project.