Den of Shadows is one of the first young adult series I've ever read, and it helped me really get into the world of YA. My interest is helped that the first four books were published when the author was a teenager; it makes me want to be a young author, too. I'll make a list of the negative and positive points. Note that I haven't yet read Token of Darkness, Poison Tree, or Promises to Keep.
- The entire thing is pretty monotone and humorless.
- The brevity can, at times, make the story difficult to get into before it's over.
- Persistence of Memory had no tension whatsoever.
- The stories are often not emotional enough to get truly invested in them.
- In the Forests of the Night was the very definition of boredom.
- Midnight Predator had no ending.
- The mood is very successfully dark and foreboding.
- The characters are always well-developed, even when they're not emotionally interesting.
- The plots are always fast-paced and suspenseful.
- The prose is unbelievably strong for something written by a teenager.
- The worldbuilding is fantastic; everything is very detailed and realistic.
- Shattered Mirror was like a thrill ride; everything moves quickly, everything is surprising, and everything is, well, thrilling.
- Demon in my View was wonderfully plotted and genuinely unpredictable.
- Actually, that unpredictability part could go for the entire series, except maybe Midnight Predator.
- All Just Glass very successfully juggled Grey And Gray Morality and its several viewpoint characters.
- Speaking of which, there's plenty of moral ambiguity.
So, overall, while it has some issues, it is definitely worth reading, particularly alongside Kiesha Ra
. I strongly recommend.