There are three characters besides Roland (The Gunslinger): Eddie, the heroin addict; Odetta Holmes/Detta Walker, the woman with dissociative identity disorder; and Mort, The Pusher. Each has their own unique story that held my interest. Two of them were also linked by events that occurred during their lifetime. All these people help Roland during his quest to The Dark Tower with which he is obsessed. Eddie even points out that Roland's heroin is the Tower and he is nothing short of an addict himself. While the book doesn't answer many questions about the tower, Roland's quest becomes much more involved and I couldn't stop turning the pages to find out what was going to happen.
I will admit there is one other set of characters that I loved: The lobstrosities! They were a constant deadly threat, but oh so yummy and I really enjoyed every moment that they were in the book. Who wouldn't love a giant lobster that was strong enough to snap off your arms and legs with its claws but provided the crew with a tasty dinner they could barbeque over the fire?! It was an animal I would definitely pay to see in a zoo and would most likely end up on one of Animal Planet's shows, The Most Extreme. I like that Stephen King found a way to put lobsters in the book since he is from Maine. It is such a huge part of the culture in that part of the country that I thought it was a nice touch to the book.
I have a tendency to get caught up in the story when I'm reading a book and miss a lot of the symbolism and other important parts of it. The Dark Tower series is full of symbolism. What is The Tower that Roland seeks? Why is his journey littered with people that he must ultimately sacrifice to reach his goal? I have more questions and hope they will be answered as the series goes on. For now, I am going to pick up another book before I return to the series in a week or two.