Dave Davies

Every time the president of the United States travels, he's accompanied by a cadre of Secret Service agents. Sometimes seen wearing crisp suits, sunglasses and ear pieces, the agents charged with protecting the president present a striking visual. But Pulitzer Prize-winning Washington Post investigative reporter Carol Leonnig says the Secret Service itself is something of a mess.

SUZANNE SIMARD says trees are "social creatures" that communicate with each other in cooperative ways that hold lessons for humans too. Simard grew up in Canadian forests as a descendant of loggers before becoming a forestry ecologist. She's now a professor of forest ecology at the University of British Columbia. She explains her research on cooperation and symbiosis in the forest, and shares her personal story in the new memoir Finding the Mother Tree: Discovering the Wisdom of the Forest.

Yale professor Dr. Phillip Atiba Goff co-founded the Center for Policing Equity, which collects data on police behavior from 18,000 law enforcement agencies across the country.