William Wisting is a 19-book series with 19 released primary works first released in 2005 with contributions by Jørn Lier Horst and Jø Lier Horst.
Book #11 «When It Grows Dark» (Når det mørkner), is a prequel to book #1 «Nøkkelvitnet» (Not translated to english). Start with book #11 if you wish to read in chronological order. Read the rest in published order.