Continuity mistake: Near the beginning of Ch. 2, it says Eddie Dean is 21 years old. But near the beginning of Ch. 3, he tells Odetta Holmes he is 23. And only about a week has passed between the two events (as Eddie says on the first page of the unnumbered chapter called 'Shuffle').
Continuity mistake: In chapter 6, when Roland first looks through Eddie's eyes in the plane, it is insinuated, upon seeing the stewardesses' uniforms, that he had never seen a woman wearing pants before. However, in the previous book, The Gunslinger, several women in the village of Tull are described wearing slacks - so while uncommon, it would not be a point of marvel to Roland.
