The best-sourced reporter covering Apple Inc., one of the world’s most secretive companies, is a 20-year-old junior at the University of Michigan. His name is Mark Gurman. He makes more than six figures a year as senior editor and scoop master at 9to5Mac.com, a news outlet most people have never heard of. In the interest of truth, which Gurman is known to pursue with almost religious zeal, it should be noted that he sometimes types stories in class.

Gurman’s scoops, beginning in high school, have included stories about Apple’s foray into tablets, new phone designs, the arrival of Siri, the dropping of Google maps, how Apple stores operate, how new operating systems work and look, and, most recently, how the company plans to integrate health and fitness tracking into its devices. Gurman’s stories serve multiple audiences. The primary one is Apple obsessives, for whom even a report on a new button design is life changing. Another is the mainstream tech press, which reads his stories for clues about Apple’s larger strategy, a Rubik’s-like puzzle given Apple’s stealthiness and complexity.

“He drives that site the way Nate Silver did at the New York Times,” said Kara Swisher, who with Walt Mossberg co-founded Re/Code, one of many outlets that have tried unsuccessfully to lure away Gurman and his scoops. “He’s the show as far as any of us are concerned in Silicon Valley. He’s the brand.”

Becoming a brand before becoming a full-fledged adult has made Gurman’s life a little peculiar to family and friends, and even, at times, to Gurman himself. One morning in the fall of 2011, at the beginning of his senior year in high school, Gurman woke up about 6 a.m. and noticed a missed call from a source. “What could they want at 2 a.m.?” he thought. Gurman fired off a text message. Through a series of exchanges during the school day, Gurman learned that his source had some incredible goods: details of the iPhone 4S and, more importantly, news of Siri. To fanatical iPhone fans, this was Pentagon Papers stuff.

A few days later, at 5 a.m., Gurman broke the news under this headline: “The new iPhone…” His lead, in bold letters: “It’s time to show our cards.” The next 1,400 or so words breathlessly disclosed everything he knew about the 4S. Like subsequent iPhone scoops, it generated more than 500,000 pageviews and dozens of copycat posts on other Apple fan and rumor sites.

“If you crack open the casing of the new iPhone, you will find significant upgrades from the iPhone 4,” Gurman wrote. “A faster new processor for better gaming and graphics. More memory to improve web browsing. A new camera for “incredibly high-resolution and clear shots.” New chips for connecting to multiple cell phone networks. He had something even bigger, a significant move by Apple to reshape how its users interacted with information on the go. “Assistant,” Gurman called it, using Apple’s internal code name.

Launched as Siri, Gurman nailed its main functions: “To activate, the user holds down the home button for a couple of seconds…and then the microphone interface ‘slides up’ from the bottom in a clever animation.” And he nailed down the way many people now use their iPhones: “Another interesting Assistant feature is the ability to create and send an SMS or iMessage with just your voice. For example, you can say ‘send a text to Mark saying I’ll be running late to lunch!’ – and it will send. This is a super compelling feature for people who cannot physically or safely take the time to type out a text message.” Mundane now, but novel at the time.

Gurman reported that the phone would be introduced on Oct. 4. A day after his post, Apple sent invitations to its unveiling, writing “Let’s Talk iPhone,” a sly hint to Siri. The invitation date: Oct. 4. Siri was a hit. Mossberg called it the “standout feature” of the new phone. David Pogue called it “mind-blowing.” Gurman’s scoops continued into the new year and beyond.

Just who it is that’s talking to German is a subject of frequent speculation among reporters, especially because of his age. The details in his stories are so specific that they must come from engineers inside, right? Or favored developers, right? Only he knows, but as Fortune once wrote, “If anyone has the goods, it’s Mark Gurman, 9to5Mac’s teen blogging phenom.”

Michael Rosenwald is a reporter at the Washington Post