If you watch Mike Judge’s brilliant HBO comedy series “Silicon Valley” (and why wouldn’t you?), then you’ll snicker at the number of times bitcoin evangelists say that they’re changing the world. In 2015 technological innovations can’t just be cool or practical; they must promise to Make the World a Better Place.

What sets the digital currency bitcoin apart is that it is actually poised to transform our lives (or at least our money), as Nathaniel Popper, a New York Times reporter, chronicles in his breezy and informative book “Digital Gold.” The question is: Is it changing the world for the better? It depends on which one of Mr. Popper’s many characters you ask.

The story of digital cash begins underground—in this case, with the cypherpunks of the late 1990s. Long before the surveillance age was making headlines, these activist coders were busy devising solutions to protect privacy and anonymity online. One of their imperatives was the creation of digital currency. “What we want is fully anonymous, ultra low transaction cost, transferable units of exchange,” as one rebel coder posted in an online forum at the time.

The benefits were multifold. No banks. No fees. No credit companies knowing how many Britney Spears songs you downloaded. Just as email and file-sharing services such as Napster were respectively overthrowing the postal system and the music industry, the invention of cryptocurrency would transform banks into, as the coder railed, “the obsolete dinosaurs they deserve to become.”

But first the code had to work. It wasn’t until 2008 that a mysterious programmer (or group of programmers) who went by the name Satoshi Nakamoto engineered a viable solution: bitcoin.