That little black book

For the past few weeks I’ve been attempting to discover the name of a book I once held in my hands, was interested in, but failed to purchase. I know it concerns mathematics. I know it has a black cover. I know I saw it on a table at Barnes and Noble within the past ten years. And I know it had a small trim size. I think it was translated from Spanish or Italian. For whatever reason it seemed interesting to me, but not enough in the moment for me to actual buy it. Now that I’ve been dabbling a bit with math again, I’m curious to find it. Every day I search a little. So far nothing. But maybe tomorrow.