Taking Lytton Strachey's Eminent Victorians as its model, Katie Roiphe's study of seven artistic couples and their tangled sexual webs risks being a kind of bluestocking Heat for the prurient literary groupie. Yet while tabloid stories of celebrity break-ups only create the lurid illusion of intimacy, Roiphe carefully reconstructs these relationships from the wordy paper trail left behind by her subjects. One bleak truth repeatedly asserts itself: no matter how free these couples tried to be, the musty-gloved hand of Victorian morals kept pinning them down. The liberated Vanessa Bell squeamishly sent Angelica - the daughter conceived with her gay lover Duncan Grant - to a "specialist" for a facts-of-life talk. HG Wells prided himself on his open marriage, but the doors remained shut for his wife, and it's unlikely his illegitimate son with Rebecca West thought it so wonderfully modern to be packed off to boarding school aged three. Other people's marriages are a mystery, but Roiphe is like a house-guest with a glass to the bedroom wall, and her insights are revelatory.