In mid December, Time Inc. was the latest in a string of companies to announce that it would start accepting bitcoin in payment, following on the heels of Dell, Overstock and Expedia who came before. You might say the age of cryptocurrency has arrived.Paul Vigna and Michael J. Casey, who write about cryptocurrency for the Wall Street Journal's MoneyBeat blog, certainly think so. They co-wrote a book on the subject called, appropriately, The Age of Cryptocurrency, out on January 27 2015 from St. Martin's Press. I recently spoke to them about the book, currency markets, the global economic order and high-net-worth investors. The central question they are trying to answer: Is bitcoin becoming money? And if so, will it allow us to bypass banks all together, and the giant tax they levy on the global economy? They see bitcoin and other cryptocurrencies ushering in a kind of radical Globalization 2.0. These new forms of money will have important implications for the world's wealthy. Below is an edited excerpt of our conversation.