A Name Unknown—July 4 Roseanna M. White. Bethany House. 432 pages. Rosemary Gresham has skills that draw the attention of the mysterious Mr. V—a man who wants her to research Mr. Peter Holstein and find evidence of his disloyalty to England. Rosemary accepts the job because the pay will keep her large family from destitution. Although her expertise involves theft, her gift for languages and study of the upper classes allows her to pose as a librarian looking for work.…