The professor of the title of this book is the survivor of a car accident which left him with a short term memory loss. His clothes are covered with pinned on notes, one of which reads "My memory only lasts for eighty minutes". The housekeeper is a single mother of a ten year old son, and she and her son gradually develop a relationship with the professor, and a love for the mathematics that is still his passion. And the professor seems to develop a relationship with them, too, even though each morning he has forgotten them and has to refer to the notes and sketch pictures pinned to his clothing that identify her as his housekeeper.
In the first section I began to wonder if I had made a good choice, as there is an extended description of how the professor asks the young boy to come up with a better way of calculating the sum of numbers from one to ten (or one to a hundred, or any other number) without adding them up. This is the sort of maths that is regularly taught to extension programmes of intermediate school age children, and I wondered if the rest of the book would be similarly tedious, but in fact it was a beautiful and tender read.
Baseball comes into it too - the son, nicknamed Root, has a passion for baseball, as does the professor, although he has never seen a game. In his case, the passion comes from numbers and statistics.
I was surprised by one thing - the meals that the housekeeper cooks seemed very Western. It describes her cooking, for instance, a roast dinner. No mention anywhere of noodles, rice, tempura or any other Japanese dish. Since the author is Japanese, I have to assume this is authentic, even though if a Western author had described Japanese meals in the same way I would have thought they had it badly wrong.