Thin Air by Ann Cleeves (Paperback, 2015)

WINNER OF THE CRIME WRITERS' ASSOCIATION DIAMOND DAGGER AWARD 2017\nThin Air is the sixth book in Ann Cleeves' Shetland series featuring Detective Jimmy Perez.\nNOW A MAJOR BBC SERIES\nA group of old university friends leave the bright lights of London and travel to Unst, Shetland's most northerly island, to celebrate the marriage of one of their friends to a Shetlander. But late on the night of the wedding party, one of them, Eleanor, disappears - apparently into thin air. It's mid-summer, a time of light nights and unexpected mists. The following day, Eleanor's friend Polly receives an email. It appears to be a suicide note, saying she'll never be found alive. And then Eleanor's body is discovered, lying in a small loch close to the cliff edge.\nDetectives Jimmy Perez and Willow Reeves are dispatched to Unst to investigate. Before she went missing, Eleanor claimed to have seen the ghost of a local child who drowned in the 1920s. Her interest in the ghost had seemed unhealthy - obse.