A Severed Head by Iris Murdoch is based in London, although the time frame is not clear. The language is somewhat timeless although the reader may imagine it as being set in the late 1960s. The voice of the story belongs to Martin Lynch-Gibbon, a 41-year-old married wine merchant.

Martin Lynch-Gibbon is one of three children, descended from an Anglo-Irish family on his father's side. Martin's mother was a Welsh painter. Martin is a tall, good-looking man with brown hair, which will eventually fade to the color of white pepper. Martin's face is long, pale and considered to be old-fashioned, a trait carried by all the Lynch-Gibbons.

The story begins with Martin having a discussion with his mistress, Georgie, a beautiful, well-educated young woman. Although the two profess to be in love it is clear that Martin will never leave his wife. Georgie does not press the issue. The reader is quickly introduced to Antonia, Martin's wife, and Palmer Anderson. Palmer Anderson is Martin's best friend and Antonia's psychoanalyst. Martin finds out early on that Antonia is having an affair with Palmer that results in Antonia asking for a divorce. Ironically, Martin is baffled and wounded. It is clear that Martin feels betrayed even though he, too, has been having an affair. The book has a great deal of mental anguish and manipulation regarding intimate relationships. Despite the devastating news, Martin claims that he loves Antonia and Palmer more than ever and cannot seem to stay away from them.

As the matter drags on, Martin's behavior becomes inconsistent and erratic. Martin finds he can not see Georgie for the present time until he can sort out the situation with Antonia. Georgie says little about Martin's comings and goings and at one point says that she pretends he does not exist when she is alone. Georgie believes that thinking about Martin when he's not there will only feed her imagination and make her miserable.

Martin's sister Rosemary attempts to help Martin separate household belongings at Hereford Square. Rosemary seems to be one of the steadier characters. Martin's behavior becomes increasingly strange as he spends a great deal of time with Antonia and Palmer. The couple consistently maintains that they cannot live life without Martin. Martin continues to be at their beck and call and even does errands for Antonia when necessary. The first errand is to pick up Palmer's Sister, Dr. Honor Klein, at the railway station. The meeting between Martin and Honor is stiff and uncomfortable at best. The pair seems to engage in ongoing arguments and snipes. At one point, Martin attacks Honor in Palmer's basement. Much of the story revolves around Martin's angst and tenuous mental ability.

Murdoch effectively creates a web of deceit and infidelity in which each main character is involved. The six main characters switch lovers, frequently and in the end, everyone leaves with a different person. Martin is left with Honor and the author signals the beginning of a tempestuous and uncertain relationship.