Haunters come from the illustrator of the Harry Potter books, which I find a pretty fascinating connection.
14-year-old David has dreams so vivid they seem real. In a dream, he saves his friend Eddie from a fire, which inexplicably makes Eddie turn against him. David finds out that his dreams are in fact forays into the past, where he appears like a ghost - but he's not the only one.
David is inducted into the Dreamwalkers Project, who are engaged against a rogue - Adam, the most powerful dreamwalker they've ever seen. Adam is working for the Haunters, a counter-organisation that is bent on reaping personal benefit by manipulating history. But there is something much more sinister happening, and Eddie is the key to it all. David and Adam must face off with each other to keep history running as it should, but who will win?
Haunters has a great concept, and although like any time-travel theory, it can't be looked at too closely, it holds together well enough for the purpose of the story. I was bothered by certain aspects of it, but they were (mildly) dealt with towards the end of the book - if that bit had come earlier, I could have enjoyed it more wholeheartedly.
Nevertheless, this is a thoroughly enjoyable read, and David's character is engaging. As other reviewers have noted, there are strong female characters (physically and emotionally) who provide a nice counterpoint from the central trio of David, Eddie and Adam. Its mood harks back to the kind of books I read when I was younger - the mysteries and discovery of secrets, the friendship and being tested, and the sense of suspense and sometimes danger. In a lot of ways, it fits into the same niche as the early Harry Potter books.
The story is self-contained and can be read as a standalone, although a sequel appears to be in the works. While it's aimed at the YA age-group, I'd easily recommend for confident readers, 9+.