...his suit was covered with innumerable scraps of notepaper, each one attached to him by a tiny binder clip. Every conceivable surface -- the collar, cuffs, pockets, hems, belt loops, and buttonholes -- was covered with notes, and the binder clips gathered the fabric of his clothing in awkward bunches. The notes were simply scraps of torn paper, some yellowing or crumbling.
The most permanent and poignant one is to remind the Professor of his own condition: "My memory lasts only eighty minutes."
It is the housekeeper (we never know her name) who tells the story of the relationship that develops between herself, the Professor (his only cognomen), and her ten year-old son, Root. Root is not the son's real name, either, but the name that the Professor gives him, saying that the flat top of the boy's head reminds him of the square root symbol.
The Professor still spends many hours each day working on proofs and thinking. Crowds and chaos distress him; numbers bring him peace. To his delight and her surprise, the housekeeper takes an interest in the numbers. She's had little education, but she is not without native intelligence, curiosity, nor humility:
There was something profound in his love for math. And it helped that he forgot what he'd taught me before, so I was free to repeat the same question until I understood. Things that most people would get the first time around might take me five, or even ten times, but I could go on asking the Professor to explain until I finally got it.
One day, a refrigerator's serial number catches her attention, and she takes a notepad and pencil from her pocket and begins to scribble.
Once I'd proved that 2,311 was prime, I put the notepad back in my pocket and went back to my cleaning, though now with a new affection for this refrigerator, which had a prime serial number. It suddenly seemed so noble, divisible by only one and itself.
The Professor loves children, and he insists that the housekeeper instruct Root to come to the cottage after school every day. They discover a shared love of baseball -- Root for the same reason that most 10 year-olds love the sport, and the Professor because the game provides him with statistics as entertainment. Root treats the Professor with great care, tip-toeing around the limits of his memory with a sensitivity rare in children. And the Professor brings Root's math homework to life.
The Professor does all of his work with a pencil on paper. No calculator or computer ever makes an appearance in this story. The housekeeper admires the way in which he draws certain numerals, some stolid and round, others slanting as if into the wind. He explains to her that although one may use a ruler to draw a straight line, it's a crude thing: fragmentary in length, since she cannot draw it out to infinity, and a real line has no width, unlike the mark of the pencil, which varies depending upon its sharpness.
"So you might wonder where you would ever find a real line -- and the answer would be, only in here." Again, he pointed at his chest, just as he had when he had taught us about imaginary numbers. "Eternal truths are ultimately invisible, and you won't find them in material things or natural phenomena, or even in human emotions. Mathematics, however, can illuminate them, can give them expression -- in fact nothing can prevent it from doing so." As I mopped the office floor, I realized how much I needed this eternal truth that the Professor had described. I needed the sense that this invisible world was somehow propping up the visible one, that this one, true line extended infinitely, without width or area, confidently piercing through the shadows. Somehow, this line would help me find peace.
If I had picked up a copy of The Housekeeper and the Professor and read the back cover, my mind would have zoomed in on the themes of mathematics and baseball, and my hand would have instinctively returned the book to the shelf. I am innumerate, and baseball bores me silly. I feel blessed that the e-book version crossed my path and that I didn't turn away from it. A beautiful, beautiful book.