The fascinating story behind the innocence movement's quest for justice.

Documentaries like Making a Murderer, the first season of Serial, and the cause celebre that was the West Memphis Three captured the attention of millions and focused the national discussion on wrongful convictions. This interest is warranted: more than 1,800 people have been set free in recent decades after being convicted of crimes they did not commit.

In response to these exonerations, federal and state governments have passed laws to prevent such injustices;...