ELIZABETH BROWN PRYOR is the author of two books about the Civil War era, Clora Barton: Professional Angel, considered the definitive biography of the pioneering nurse, educator, and Red Cross organizer, and Reading the Man: A Portrait of Robert E. Lee through His Private Letters. The latter has been praised as much for its insights into Lee, based on previously unexamined correspondence, as for its unusual organization. Each chapter opens with a long quoted letter, making the reader a partner in the process of discovering the man behind the words. Pryor, it turns out, has only been moonlighting as a historian. In her day job, she has been a highly decorated employee of the State Department with the kind of responsibilities-negotiating arms control treaties, for instance -that would keep most other people from fulfilling an ambitious scholarly agenda in their spare time. And yet her curriculum vitae reminds us that public service is not at all inconsistent with the life of the mind.