Apples Never Fall by Liane Moriarty
From the outside, the Delaneys appear to be an enviably contented family. Even after all these years, former tennis coaches Joy and Stan are still winning tournaments, and now they've sold the family business they have all the time in the world to learn how to 'relax'. Their four adult children are busy living their own lives, and while it could be argued they never quite achieved their destinies, no-one ever says that out loud. But now Joy Delaney has disappeared and her children are re-examining their parents' marriage and their family history with fresh, frightened eyes. Is her disappearance related to their mysterious house guest from last year? Or were things never as rosy as they seemed in the Delaney household?