Twenty-one books

( A Conspiracy of Truths, A Choir of Lies, The Twisted Ones, Gideon the Ninth, Ghost Talkers, The Raven Boys, A Study in Scarlet, A Conspiracy in Belgravia, The Hollow of Fear, The Art of Theft, The Ninth House, Trail of Lightning, The Outside, Spinning Silver, The Bullet-Catcher's Daughter, Paladin's Grace, The Ten Thousand Doors of January, The Spirit Ring, Red Rising, Terminus )