A ramshackle rooftop shed has been given new life as a book-lined writers' aerie.  The north-facing writing room provides a layout table and desks with views to Midtown.  The elliptical tower that divides the space conceals a restroom and a kitchen.  To the south, the reading room is a retreat from the bustling office below, its twentieth-century Modern furnishings accommodating private dining and quiet time with books or a movie.  A bamboo-shaded south-facing terrace is a skyline setting for al fresco lunches and sunset cocktails.