A psychologist perceives loneliness as a single, simple category of mental or social discomfort whose sufferers include many Americans who live alone; some bootstrap hints to ward off those lonesome blues are included. Early on, Powell cites a number of studies that show those who live alone have no more problems mentally or socially than those who live with others. Nonetheless, she plows along, presenting her thoughts about loneliness through a seemingly endless parade of case histories. More than nine out of ten of these are about mature women who are divorced or widowed. Though Powell never says so, it becomes clear that while she includes a case history of a man every now and then, she is really talking about lonely women. Powell says that 20 million Americans currently are living alone and her book is addressed to those of them who ""wish to be productive and fulfilled without being lonely."" This prescription probably fits almost every one of those 20 million loners. And that is the problem: the category of loneliness is so broad as to be useless as a diagnostic or treatment tool. There are a great many causes--and effects. Any book that attempts to deal with such a broad subject of necessity becomes a grab-bag of symptoms and proposed cures of little use to any one reader. And in this instance the suggestions for dealing with loneliness tend toward the obvious and simple-minded--such as getting out and about through joining a tennis group, a church, a sewing circle. Mushy thoughts about a mushy subject in mushy prose.