‘The Nightmare’ by Lars Kepler
In “The Hypnotist,’’ Lars Kepler’s first book, Joona Linna shared top billing with a second character. Now in “The Nightmare,’’ the second Kepler book to hit the States, the narrative is all his, and he flowers in all his freakish glory. He is something of a Clues Whisperer, sensing the presence of information hiding in the periphery. In short, he’s the kind of character you can build a franchise around.