The Sum of Things is the last book in Olivia Manning’s The Fortunes of War, the third volume of The Levant Trilogy. Like the last two volumes, the novel alternates point of view between the young soldier, Simon Boulderstone, and the young wife, Harriet Pringle. In this last volume, we also get Guy Pringle’s point of view.
At the end of the last book, Harriet was to set sail unwillingly on the Queen of Sparta to return home. Guy thought it would be best for her health, and Harriet only agreed because she was despairing of her marriage. However, at the last minute she did not embark, instead taking a transport to Syria with an acquaintance to visit Adrian Pratt.
She doesn’t know that the Queen of Sparta was torpedoed with only one passenger surviving. Back in Cairo, Guy believes her to be dead and starts to realize he neglected her.
Also at the end of the last book, Simon hit a mine. He finds himself in a hospital for paraplegics with the fear that he may be permanently paralyzed.
When Harriet reaches Syria, she finds Adrian Pratt gone, transferred to another post. Only then does she begin to wonder what she will do, as she has very little money.
This was a satisfying and effective conclusion to the six-volume series about the adventures of Guy and Harriet during the war. Although I started out not liking Harriet, the characters grew on me and I was always interested to see what would happen to them.
What? Me Read? 
I loved that series and can see that it’s one of the few that I might want to re-read at some point.