Bill Moyers’ guest this week couldn’t be more timely. After the verdict in the case of the man who killed Trayvon Martin, Moyers interviews author Tom Diaz about the country’s concealed-weapon and self-defense laws, backed by the NRA. The title of Diaz’s book is The Last Gun: How Changes in the Gun Industry are Killing Americans, and What It Will Take to Stop It. Moyers & Company is televised Friday through Sunday on local TV stations. To find when and where it airs in your area, see the Moyers & Company website.