What's the truth about Bitcoin? Critics couldn't be clearer: it's a fad that can’t decide whether it’s a currency or a speculative investment. 'You’re betting, essentially, on being the last person holding the bomb before it goes off,' wrote Sam Leith on Coffee House. Many others agree. But Bitcoin's critics are wrong: there's nothing faddish about it. Bitcoin is a monetary revolution and is here to stay. Perhaps it's no surprise that Bitcoin has attracted its sceptics. Understanding what it's about isn't easy. In short, Bitcoin is a monetary network, an incorruptible ledger, with the money supply fixed by code (there will only ever be 21 million Bitcoin). It allows anyone with an internet connection to engage in a transaction that cannot be altered or stopped, with currency that cannot be seized, all without requiring a middleman such as a bank.