The book that Eric was reading while lounging on a snow-covered mountaintop in Sweden was "Den allvarsamma leken" by Hjalmar Soderberg. An EW Popwatch article explained that Alexander Skarsgård chose the book because it is an 'old Swedish favorite.' The book is about a man and woman who fall in love, but choose to marry other people. Trapped inside loveless marriages, they reunite with tragic results.
Every episode is named after the song that plays during the end credits. "Radioactive" is by Imagine Dragons.