What have I done to my back? I spent the last day and a half on the sofa and the only galley I had at my fingertips was ELIN HILDERBRAND'S "THE CASTAWAYS". I have not read one of her novels until now, because as a devoted annual visitor to Nantucket, I've questioned whether any author could do the Grey Lady justice in a beach read. I started the novel, flat on my back, at 5:30 yesterday and by tea time this afternoon I was finished. The perfect length for a beach read, and also for healing an ailing back. The four young and appealing couples who are the best of friends are united by their love of their life on Nantucket, their families and the deep friendships with each other. A sailing accident claims the life of one of the couples who have been suffering their own personal tragedy and marital discord and send the other couples into various states of grief. The mystery surrounding the accident brings about surprising discoveries of the relationships between the individuals. Good summer read!