A definitive new biography takes in adventures on the Mississippi, racist stereotypes and get-rich-quick schemesIn his lifetime, Mark Twain was the greatest literary celebrity the world had ever known. In the US, he hobnobbed with presidents; on his many travels, he would dine privately with the German kaiser, the Austrian emperor, or the Prince of Wales. Visiting England to collect an honorary degree from Oxford University, he was cheered off his ship by the stevedores of the London docks, before making his way to Windsor Castle for tea with the king and queen.He was the bracing, irreverently humorous voice of America. Like Charles Dickens, whom he heard read from his own work in New York, he became a performer as well as an author. In London he was feted when he read passages from his travelogue of the Wild West, Roughing It. Everyone loved the “twang of his drawl”. He went on to take his work in progress, Huckleberry Finn, round more than 100 American towns and cities, earning ha...