Gilbert Marshall did not seem like the type of man who would commit murder. That sort of thing was not for people in his position. People envied him his wife Pamela, who was well-groomed and beautiful; but Gilbert had long ceased to think of her as a wife, or even as a companion. When the polished Edward appeared on the scene, both Gilbert's and Pamela's lives were changed; as was Gilbert's long-cherished murder plan.
A "why-" or "how-" done it rather than a who-done it. Unpleasant lead character and I didn't like the writing style. I was surprised that it was "first published" in the mid-1980s. I would have guessed the 1950s from the tone and the way that the women and workplace are described.