When your book is in its 10th edition and remains the authoritative tome on its subject, you’re probably doing something right. Even so, mega-attorney and author Don Passman admits, the 10th edition of his All You Need to Know About the Music Business (Simon & Schuster) required the most extensive revision since the first.

You won’t be stunned to learn that the changes wrought by streaming were the biggest reason. The now-dominant mode of music consumption “has really upended the entire economic model of the business,” Passman says, explaining that hitherto, “people monetized music by selling something. It was a piano roll. It was a wax cylinder. Now, for the first time in history, you’re not getting money from selling; you’re getting money from people listening.”

In the prior edition of his book, he notes, “I was using sales as model of metric and using CDs as the first royalty calculation. All of that’s quickly becoming irrelevant.”

Passman confirms that the streaming economy, which has doubtless resuscitated the industry, has been challenging for artists. “There’s a finite amount of [subscription] money every month,” he emphasizes, “so every time somebody listens to me, they’re not listening to you. In other words, the bigger piece of the pie I get, the less you get.

“The biggest challenge in updating the book was just how much of a moving target the industry has become,” he notes, which is why this edition took a year longer than preceding rewrites. He ultimately had to content himself with “a snapshot of where we are now—or at least most of the way there. I’m sure it’ll change again.”

In addition to streaming’s rise, the declining significance of the album—upon which recording deals had always been founded—is another issue with which the biz is grappling. “People may not even make albums in the next few years,” he marvels. “Yet most contracts are based on delivery of albums, and if the album disappears, how do you ever finish your deal?”

The rise of social media represents yet another profound shift in the landscape, Passman says. With the barrier to distribute music so low—and the ability to build a huge audience now in artists’ hands—there are tens of millions of songs out there, and the biz is struggling to figure out what will cut through the noise. “The labels want to see something happening before they get involved,” he says. “I think that’s why we’re moving more toward data-driven signings, based on things that are already getting some traction.”

When asked about the skyrocketing price of publishing deals, he’s typically philosophical. “These are very high prices, the highest I’ve seen in my career for some of the catalogs. The deals are in large part based on the idea that future streaming will float all the boats up, even more than it’s doing now, and therefore these multiples won’t be as crazy-looking as they are today.” But, he cautions, “nothing goes up forever. Streaming isn’t at saturation yet, in most markets, but when it is, the income could flatten until subscription prices go up.”

Despite streaming’s dominance, Passman observes, “The record companies still haven’t figured out who should be doing what in the streaming world. Data, sales, marketing—they’re all kind of growing together in a way that’s not settled or finalized. When you put an ad on a streaming service, is that sales or marketing? Who deals with DSPs, and who deals with consumers? Where does data fit in?”

"The biggest challenge in updating the book," he says, "was just how much of a moving target the industry has become."

But even amid all this transition, Passman insists, the attorney’s role has remained constant. “The specifics have changed,” he says, “but the roles are the same—get the best deal for the artist.”

Passman says he’s always enjoyed making contract law, royalty calculations and other eye-glazing matters accessible; “Once I understood a really complicated topic,” he says, “I could explain it simply. It’s just something that comes easily to me.”

Not that being a top attorney and an author of a still-in-demand industry text are enough to absorb the man’s copious energy. He’s also a novelist, a magician, an avid poker player (and fledgling backgammon enthusiast) and devoted World Series of Poker attendee with his son. “I’m a serial obsessive,” he explains, “so I’ll get involved in something, do it intently, and then move on to something else. But at the moment, those are the obsessions.”