One thing I love about my work is how it allows me to meet, interview and write about newsmakers and game-changers -- people on the cutting edge of environmentalism, science, the law, energy, the arts and more. Over the course of 12 nonfiction books, I've met quite a few, and readers often ask me what's become of them. So here are updates on six reader favorites, people who have changed lives and the world:

Doug and Kris Tompkins, environmental philanthropists

In Eco Barons, I wrote about Doug Tompkins, the cofounder of Esprit who cashed out to become one of the world's leading environmental crusaders. With his wife, Kris McDivett Tompkins, former CEO of Patagonia, he has created a million acres of parks and preserves in the Patagonia region of Chile and Argentina. Update: These days the Tompkins are battling hydro-electric dams in one of the world's last big wild places, while completing South America's Yellowstone, Patagonia National Park. Here's an excerpt about Tompkins from Eco Barons.

Roosevelt Dorn, the judge who would be king

When I spent a year inside the LA Juvenile Court for No Matter How Loud I Shout, Judge Dorn was at the epicenter of a system overloaded, undermanned and at war with itself. With the booming voice of a old-school preacher and a pistol tucked inside his robes, Dorn saved kids. But he didn't mind bending the rules, and he left office a polarizing figure. When he became mayor of Inglewood, his fall from grace was spectacular, ending with a public corruption conviction, as reported in the LA Times. Here's an excerpt about Dorn from No Matter How Loud I Shout.

Arthur Penn, from GI Bill to Hollywood icon

Over Here: How the G.I. Bill Transformed the American Dream featured Penn, the director of such groundbreaking films as Bonnie and Clyde and The Miracle Worker (not to mention the televised Kennedy-Nixon debates). Penn credited his success on his experience at the experimental, arts-centric Black Mountain College. A veteran of the decisive World War II Battle of the Bulge, Penn told me he would likely never have gone to college without the GI Bill -- one of the many stories I recounted in Over Here. Penn has since passed away at age 88, but the G.I. Bill continues to aid new generations of veterans returning from Iraq and Afghanistan. BTW, a new ebook edition of Over Here is in the works.

Judge John E. Jones III and the new Scopes Trial

In Monkey Girl I chronicled a modern-day Scopes Monkey Trial, which ended with Judge Jones's ruling that a creationism offshoot known as intelligent design could not be taught alongside evolution in a public school science class. Jones didn't stop making news with that controversial Kitzmiller v. Dover case, however. These days he's in the middle of another no-holds-barred fight with national implications, as he presides over a suit brought against the natural gas industry by Pennsylvanians who claim their water and health has been destroyed by a newly popular method of drilling called fracking. Here's an excerpt from Monkey Girl.

Roxanne Quimby, Burt's Bees and the Maine Woods

When I wrote about Quimby in Eco Barons, the founder of Burt's Bees (who built a fortune from a company originally based in a log cabin with no electricity) was busily preserving large swaths of the vast Maine Woods that long ago enraptured Henry David Thoreau. Update: Quimby is trying to donate much of the land she purchased in order to create a new national park in Maine. Not everyone in the state is thrilled, and the would-be gift has turned into a battle, according to Forbes.