WASHINGTON -- It is vacation time, and this summer millions of Americans are going to take breaks from their daily toils. Many will seek out quiet spots to relax with family members. They will head to the beach or to campsites, and some will defy gas prices and head for the open road. The summer vacation is a perfect time to read a book, possibly two books. There are all kinds of books available: personal improvement books, how-to books, bad books, very bad books. For some reason, the books I have been reading this summer have been mostly history books....