A book that I noticed mainly because I myself am plagued by insomnia, it surprised and delighted...I mean, pleased, me. The story flowed quite well, and I loved the references to other stephen king books (if you read pet sematary, you will mutter, "heyyyy..." when the character notices a childs cap filled with blood). It really isnt much of a horror, more of a sci fi thriller, but it does have its "scary parts" (I like to think I have been desenseitized to horror due to my early and prolonged exposure to it). I really liked king's accurate portrayol of insomnia, it really isnt a complete lack of sleep in most cases, mostly just a smaller or steadily shrinking sleep of poor quality.
The characters are likeable and beleivable, and yuo feel closer to them because of the included pet names given to them from other fellow senior citizens (such as naive louis' "our louis" saying). The ending was rather enfuriating, but understandably so, and the main villain is really fleshed out, so that you start to pity it, even while you root for its downfall. It is a rather mammoth of a book, but much like my beloved Wizard's First Rule, this is a plus for me. Although it is large, I read through it rather quickly for me (A decent five hundred page book will take me about a day, if I dont like it, two) and I think that this will be a plus for you as well, as long as you arent intimadated by it's leviathan appearance.