As the first line in the "Dark Tower" series, it begins a story King intended to be the longest popular novel in history.

The "Dark Tower" series is not the longest popular novel ever written, but it's easily the one with the highest body count.

The Dark Tower series has a long and convoluted publishing history.

Stephen King saw the Dark Tower series as a first draft.

King said, regarding the Dark Tower series, "It's not really done yet.

He started to write the first story in The Dark Tower series on coloured library paper.

King makes this point when he explains how The Dark Tower series ends.

It is alluded to more directly in volume six of his "Dark Tower" series.

Also, deathbags and blue auras are present in the Dark Tower series.

The constant readers of the Dark Tower series may realize that is not necessarily a continuity error, but a clue.