The middle years, caught between children and parents, free of neither: the past stretches back too densely, it is too thickly populated, the future has not thinned yet."" That is the emotional territory where sit, jelled, the four main characters of Drabble's new, loose, London-based, sympathetic, and loopingly optimistic novel. One's a social worker; one a journalist who lost an arm years ago in Kurdistan; one's a doctor; and chiefly--although the main ""character"" here often seems to be the ludicrously resilient nature of forty-ish friendship itself--there is Kate Armstrong. A magazine columnist who was early on the bead of ""women's subjects"" (""menstruation, battered wives, low career expectations""), Kate--now in her forties--is unsure of what lies ahead. She's already divorced. Her children are about ready to leave. She's deeply, inextricably tangled in the lives of her friends: the doctor, Kate's ex-lover, is married to social-worker Evelyn; all three are friends of one-armed journalist Hugo. And Kate knows that what's still to come may be grim--death of children, freak violence, aging, unlovableness, financial insecurity. But finally she chooses to turn herself toward it with a sort of scruffy, disorganized hopefulness. Told almost completely in a series of ruminations (Kate's and her friends'), the book has a vulnerable, occasionally fey, but almost consistently charming lurch to it--a weather of Look! We've come through, a gathered and informal warmth. Indeed, with each succeeding novel, Drabble appears to edge ever closer to being E. M. Forster's heir: rich works, turned and molded by helpless circumstance, about the apprehensions and redemptions of staying responsible. And though nigh-plotless, almost sieve-like in fact, this new book presses that impression deepest.