Lord Northcliffe, the brash young newspaper baron, was perhaps the most hated man in England during the First World War. The upper class banned his papers from their clubs and ceremonially burnt them at the Stock Exchange, while pacifists, socialists and many others damned him as a warmonger. Middle England, however, went on buying his newspapers, as it had been doing in increasing numbers for nearly twenty years. And this latest biography, marking a century since he died, says the readers—and Northcliffe—were often right. Northcliffe’s problem on the Left was that his papers warned for years before the war about…