As many constant readers know, Stephen King likes to tie a lot of his works together, creating his own multiverse, and The Dark Tower series is probably one of the biggest examples. Here's a list of his works that tie into The Dark Tower in some way, shape or form. The books are listed in suggested reading order. Anything after the last novel can be read in any order. Time is unlimited, and remember, all things serve the beam. Long days and pleasant nights.