AN INSTANT SUNDAY TIMES BESTSELLERAN INSTANT NEW YORK TIMES BESTSELLERA REESE'S BOOK CLUB PICK'The Sanatorium will keep you checking over your shoulder. This spine-tingling, atmospheric thriller has it all: an eerie Alpine setting, sharp prose, and twists you'll never see coming. A must-read.' Richard Osman'An eerie, atmospheric novel that had me completely on the edge of my seat.' Reese Witherspoon EVERYONE'S IN DANGER. ANYONE COULD BE NEXT. An imposing, isolated hotel, high up in the Swiss Alps, is the last place Elin Warner wants to be. But she's taken..