What You Don't Know, Sandi Wallace

A stand-alone novel from Australian author, Sandi Wallace, WHAT YOU DON'T KNOW is set on a secluded island where Tess works at home, writing children's mystery books, and her travelling husband returns to on weekends from the job he loves, to a wife that he adores. It seems, to all the world, like the perfect life, enough neighbours to create a sense of community, enough distance to create a buffer, a sense of sanctuary, even a goofy chocolate labrador dog. A feeling shattered by sightings of a prowler, triggering unresolved trauma for Tess - her best friend's death was never explained, and suddenly Tess is doing all sorts of odd things she can't explain, and Joe seems to be hiding something. Then a young local woman is abducted and what seemed idyllic suddenly starts to look very shakey indeed.

The use of secrets and past events to set up a present day threat isn't new territory in crime fiction, but WHAT YOU DON'T KNOW uses them, and the isolated, almost locked room setting, to good effect. The inclusion of electronic stalking and hijacked communication is also a very current day and real threat, which creates a sense of immediacy and overall / overwhelming threat here that invokes such confusion in Tess, and therefore becomes increasingly unsettling - the idea of who you can trust when everything suddenly gets very odd is palpable here.

The setting is well invoked as well - small community / small island and the immediacy of the weather and the remoteness is cleverly done, as is the author's own knowledge of the solitary life of an author, made even more stark by Joe's long absences from home. His reasons for being away - a salesman on the road selling environmentally-friendly insulation is plausible, but on the home front there's a neighbour who has suddenly started behaving oddly, and some weird in house things - passages of text appearing in her work in progress, things moving / going missing / adding to the presence of that stalker, meaning a constant ramping up of the pressure, tension and fear. And, in something that is again all too believable, a lurking property developer, pushy and unpleasant.

Meanwhile there's Kathy, held captive for nearly forty years, keeping her feelings on scraps of paper, determined to never let her much older captor break her spirit.

So a lot going on, much of which has Tess as the obvious connection, which will leave the reader really wondering about her sanity, whilst also open to questioning Joe's commitment to his wife, or maybe there's something dodgy about the neighbours and the island in general, whilst always there's the thought of who on earth Kathy is in the background. 

Whilst it could all sound very busy, the pace is high, and events, and introductions to a lot of people and situations roll out quickly, with the reader never struggling to keep track of who or what although why doesn't become clear (as you'd expect) until you get to the ending of what was a very believable, tension packed ride of a novel.