I read Stephen King's The Outsider about a year ago, which HBO adapted into a miniseries. The show began in January and recently aired its 10th and final episode (I'm assuming). Thus, I gave it a watch.
Let me start with a look back on the book. I enjoyed quite a bit about it. The story had a lot of cool and fascinating, dark ideas. But there was something I didn't at the time quite put my finger on that I think detracted from it. Ultimately, I have the book four stars. Now that I've seen the TV adaptation, I think I've sorted it out.
But let me mention some high lights. First, the mood in the series was spot on. I was attracted to the talent involved. I like Jason Bateman, who played a key role and directed a couple of episodes. The rest of the cast is excellent, particularly Cynthia Erivo. I also found the adaptation to have a lot of fidelity to the book. There were some superficial changes. The adaptation took place in Georgia while the book was set in Oklahoma. (I'm sure production incentives are responsible for that,) There were also a few secondary characters altered. One secondary character had a mother in the book with a tiny part, which they shifted to a brother in the adaptation. I don't consider fidelity necessarily a defining point of quality in an adaptation, mostly I feel that the changes are valid so long as they bring something new. Still, in this case, where the changes are small and mostly insignificant, it can be a positive. At least they didn't change something radically and not deliver added value with the change. Altogether, I'd say its a good adaptation and an entertaining watch.
But here's the trouble, I think this story, both book, and adaptation, fail in two key points—first, the suspension of disbelief. When you tell a story, if you are going to have magic or creatures, or anything supernatural, you have to control the suspension of disbelief for the audience. If you don't, you can give them a shock that kills that story, a surprise that is too out of left-field to swallow. If magic is going to play a part in your story, you can't introduce it in the last act; it's off-putting. You have to suggest that possibility at least early in the story. Imagine reading a mystery, something like a police procedural, trying to figure out who killed so and so, only to have a new character show up in the last 20 pages, who ends up being guilty. You'd be angry that you never heard of the character. It's the same with the supernatural. In The Outsider, there is a supernatural element in the story, but it starts as a murder mystery from the POV of the detective trying to close the case. It doesn't really give us a peek at the supernatural element for a while. It's not so bad as to not appear until the last act, but probably not until a quarter of the way into the story, and I think it still manages to be problematic.
Second, one of the book's strengths is in character development. We get to know the lives of something in the range of a dozen characters who are either the people hunting the bad guy or a few who are his victims. But this proves to be a weakness as well, because the antagonist, the bad guy, who is essentially a boogie man, is almost completely undeveloped. By contrast, this, too, is awkward. He's not a creature who we might think of as animalistic. He posses as and acts like a regular person, and thus we can presume he has human intellect at the least. Yet, about the only motive we're given for his terrible acts is that he's hungry. We know he's capable of really horrific acts, but have no real understanding of why he's ok with doing them. Thus the character falls flat, and it's hard to endure through a long book or 10 hours of a tv series.
In short, the adaptation captures the novel well, but in turn shares the books weaknesses.