Hundreds of thousands of Americans currently are purchasing and avidly reading two monumental biographies about two monumental figures in world and American history. In position No. 1 on every best-seller list is Walter Isaacson's 900-page review of the life and achievements of Leonardo da Vinci. The other, ranked closely behind and almost as large, is Ron Chernow's review of the battles and U.S. presidency of Ulysses S. Grant.

Many such purchasers will soon discover that they have accidentally bought guidebooks to their next travel itinerary. Rarely have two such tomes performed that function better. And though both books are, perhaps, overly heavy additions to your luggage, both are superb introductions to the city-by-city and place-by-place attractions of travel.

Isaacson's biography, "Leonardo Da Vinci," is about the art and inventions of a universal Renaissance genius, a remarkable talent whose paintings, among other feats, are described without exaggeration as the best ever created by a single human being. Da Vinci's "Mona Lisa" (seen today in Paris' Louvre Museum), "Last Supper" (viewed in Milan), "Virgin of the Rocks" (National Gallery, London) and his notebooks (of which a few are seen in London's Victoria and Albert Museum) are indispensable attractions and stops on any trip to Europe (in addition to which, there are a dozen other magnificent works viewed elsewhere in Europe).

What is especially unique among Isaacson's history of each such work are 20-page reviews of the artistic choices made by this genius to achieve the greatness of each painting. Though scores — and indeed, hundreds — of other connoisseurs have written similar analyses, Isaacson's are perhaps the most easily understood and comfortably presented of any recent work. By carrying the book with you as you travel through Europe, and carefully consulting each analysis as you stop to view each painting, you greatly expand your understanding and immensely add to your pleasure.

As for Chernow's "Grant," the Civil War hero is perhaps of lesser interest to some, but followers of his fascinating history will want to visit the sites of his greatest victories: Vicksburg, Petersburg, Shiloh, Appomattox and more, where the biographer provides massive details of topography and tactics. Again, the book can add immeasurably to your understanding of each historic battleground.

Don't leave those books on the shelf at home. Each is a remarkable travel guide.

Arthur Frommer is the pioneering founder of the Frommer's Travel Guide book series. He co-hosts the radio program, The Travel Show, with his travel correspondent daughter Pauline Frommer. Find more destinations online and read Arthur Frommer's blog at frommers.com.