First published back in 1987, `Valley of Lights' was Gallagher's eighth full length novel to be published.
This murder mystery meets sci-fi horror tale draws heavily from Jack Sholder's film of the same year titled `The Hidden'.
Written predominantly from the first person point of view of Sergeant Alex Volchak, the tale quickly takes on the mysterious storyline of unconnected members of the public being found in comatose states around Phoenix, Arizona (hence the novel's title).
The reader follows Sgt Volchak's job of uncovering the true reason for what is happening to these individuals and how it is connected to a spree of grisly murders that are sprouting up around the city.
Gallagher delivers an atmospheric and tension laced tale, that builds up in pace throughout. The plot carefully intertwines the personal sub-plots and relationship Volchak has with his next door neighbour, bringing together an intense story and character rich read.
With a storyline that unfolds to reveal a somewhat paranormal reality, Volchak is faced with the dilemma of trying to bring these horrifying murders to an end on his own, otherwise the possibility of him being classed as insane would be the more likely outcome.
Taking on a not entirely original plot, the novel still remains an enjoyable read throughout, with a well written approach that delivers a dark atmospheric scenario and a haunting feeling of loneliness.
Not a particularly long novel, `Valley of Lights' lasts for a mere 191 pages in total.