A year after they married in 1962, Anne and David Bromer began collecting rare books. Anne was no rookie, having earned a master's degree in library science at Simmons College, and David "was always collecting something." The couple planned subsequent vacations around visits to dealers. A dozen years later they established a full-time mail-order dealership in rare books, working out of their Watertown, Mass. home. They now specialize in private-press books (lavishly designed volumes in limited editions), particularly illustrated, juvenile and miniature books.