"The Last Stone," a new non-fiction work, has a great deal to recommend it. It concerns one of the most famous cases in Maryland history, in which two young sisters went missing from a Maryland shopping mall. This was odd because it's rare for more than one child to go missing at once. Also, at least one of the parents was a local celebrity. The case inspired novelist Laura Lippman, who sometimes uses real-world tragedies to fuel the plots of her modern-day Gothic novels. But the story "went cold" for many, many years. Decades. What can you do if you don't have a body to work with? If you don't have a scrap of physical evidence? Then everything changed. Here's what I love in this story: Discovery is looking at the thing everyone looks at--but spotting something new. An apparent witness to the abduction noticed that the (alleged) bad guy walked with a limp. Many years after the abduction, a cold case specialist had a guy in mind, and that guy ...