Dave Davies

Thor Hanson's new book looks at the evolutionary significance of feathers in birds. Hanson tells Fresh Air that he's amazed by birds' magnitude of feathers, how feathers grow and how they're the "most efficient insulation known."

In The Long Road to Antietam, historian Richard Slotkin traces how both Northern and Southern strategies changed in the summer of 1862, when both sides committed to an all-out total war, and Lincoln squared off against Gen. George McClellan.

Jill Tarter works at the SETI Institute, where scientists seek evidence of extraterrestrial lie in the universe by looking for some signatures of its technology. "The amount of searching that we've done in 50 years is equivalent to scooping one 8-ounce glass out of the Earth's ocean," she says.

The actress play smart, tough Secretary of State Elaine Barrish in the new USA Network miniseries Political Animals. It's another strong role for Weaver, who has starred in films like Alien, Ghostbusters and Gorillas in the Mist.

Nora Ephron, the essayist, novelist, screenwriter and film director, died Tuesday night in Manhattan. She was 71, and suffered from leukemia. Fresh Air remembers the creator of Silkwood and When Harry Met Sally with excerpts from a 2006 interview from WHYY's Radio Times.

Kristen Iversen spent her childhood in the 1960s in Colorado near the Rocky Flats nuclear weapons factory, playing in fields that now appear to have been contaminated with plutonium. In Full Body Burden, she investigates the environmental scandal involving nuclear contamination around her childhood home.

Louisiana imprisons more people per capita than any other state or country in the world. One out of every 86 adults in the state is behind bars. Times-Picayune reporter Cindy Chang says the state's correctional system has created financial incentives for local sheriffs to keep prisons full.

Parents should be paying very close attention to the digital media their children are using, says child advocate James Steyer. "Young people in particular often self-reveal before they self-reflect," he says. "There is no eraser button today for youthful indiscretion."

One-third of American today are obese, and another third are overweight. A new HBO documentary series, The Weight of the Nation, explores how our country got this way and what can be done to tackle the growing national health crisis.

Two reporters for The New York Times detail their monthlong investigation of America's racetracks. Since 2009, more than 6.600 horses have broken down or showed signs of injury at U.S. racetracks, a rate much higher than in other countries.