Edward Rutherfurd belongs to the James Michener school: he writes big, sprawling history-by- the-pound. His novel, London, stretches two millennia all the way from Roman times to the present. The author places his vignettes at the most dramatic moments of that city's history, leaping from Caesar's invasion to the Norman Conquest to the Great Fire to (of course) the Blitz, with many stops in between. London is ambitious, and students of English history will eat it up. The author doesn't skimp on historical detail, and that's a signal pleasure of the book. Ultimately, though, the structure of the novel determines the lion's share of its success. Rutherfurd is a good storyteller and each vignette makes for a good story; however, he has given himself the inevitable task of beginning what amounts to a new book every 40 pages or so. Just as one begins to warm to the characters, they are hurried off the stage. You can't read London without a scorecard-but that's part of the fun.