Most readers have probably heard of Bitcoin, the digital coin that dominates the cryptocurrency market. It has gained notice both because of its skyrocketing value (from less than a cent in early 2010 to around $2,600 currently) and because it is frequently a key player in hacking- and black-market-related stories, from the looting of nearly half a billion dollars in coins from the Mt. Gox exchange in 2014 to the recent demand for payment in Bitcoin in the WannaCry ransomware attack. (For the uninitiated, here is a useful primer on Bitcoin.)

But do you know Ethereum, with a total value of coins in circulation of close to $20 billion? Bitcoin Cash, which split off from the original Bitcoin on Aug. 1, lost about half its value within hours, then nearly quadrupled by the next day? Or, rounding out the Big Four, Ripple — whose currency is known as XRP — which shot up to about 40 cents by mid-May from less than a cent at the end of March? (Full disclosure: I owned but unloaded three of these currencies before writing this article.) Then there are over 800 lower-value and often creatively named coins among those listed on Coinmarketcap.com. One can buy FedoraCoin (its jaunty symbol being the Justin Timberlake-approved hat), CannabisCoin (one guess what it looks like) or, to choose one of many bringing up the rear, Quartz, currently priced around three-thousandths of a cent. (Bad news for those who bought it at just under $2 at the end of May.)

After years as a niche market for technologically sophisticated anarchists and libertarians excited about a decentralized financial network not under government control, digital coins may be on the verge of going mainstream. “It’s the wild, wild West,” said Ron Ginn, 35, founder of a private photo-sharing service called Text Event Pics in St. Augustine, Fla., who has taken all his money out of the stock market and put it into Ripple and real estate. “This is like getting to invest in the internet in the ’90s. I’m obviously very bullish, but I expect to make a couple million dollars off very little money. This is the opportunity of a lifetime. Finance is getting its internet.”

Cryptocurrency has understandable appeal to millennials who came of age during the 2008 financial crisis and are now watching the rise of antiglobalist populism threaten the stability of the international economy.