(literally "The Professor's Beloved Equation") is a novel by Yōko Ogawa set in modern-day Japan. It was published in Japan in August 2003, by Shinchosha. In 2009, the English translation by Stephen Snyder was published. Background The story centers around a mathematician, "the Professor," who suffered brain damage in a traffic accident in 1975 and since then can produce only 80 minutes' worth of memories, and his interactions with a housekeeper (the narrator) and her son "Root" as the Professor shares the beauty of equations with them. The novel's bibliography lists the book The Man Who Loved Only Numbers, a biography of the mathematician Paul Erdős. It has been said that Erdős was used as a model for the Professor. The novel received the Hon'ya Taisho award, was adapted into a film version in January 2006, and after being published in paperback in December 2005, sold one million copies in two months, faster than any other Shinchosha paperback. Plot summary The narrator's housekeeping agency dispatches her to the house of the Professor, a former mathematician who can remember new memories for only 80 minutes. She is more than a little frustrated to find that he loves only mathematics and shows no interest whatsoever in anything or anyone else. One day, upon learning that she has a 10-year-old son waiting home alone until late at night every day, the Professor flies into a rage and tells the narrator to have her son come to his home directly from school from that day on. The next day, her son comes and the Professor nicknames him "Root". From then on, their days begin to be filled with warmth. Characters The Professor 64 years old. A former university professor who specializes in algebraic number theory. He loves mathematics, children, and the Hanshin Tigers (especially Yutaka Enatsu, who was playing for the Tigers at the time of the Professor's accident and whose uniform number was 28, the second smallest perfect number). After being in an auto accident at the age of 47, he can retain new memories for only 80 minutes. He keeps important information on notes that are attached all over his suits. He keeps baseball cards and other important mementos in a cookie tin. He has trouble interacting with other people and a habit of talking about numbers when he does not know what else to say. He has a talent for reading