My editor asked how much of the math in the novel is real. All the important stuff is 100 percent true. Then there’s some fun stuff that’s 100 percent made up. I like the mix. Below is a portrait of the man who was the mentor to many of the mathematicians in the novel, Andrei Kolmogorov. He’s definitely not made up. He liked to jump into ice cold lakes. So do I. Tomorrow I go back into character and work on the second round of edits. Two more weeks and this book will be off to the copy editor and I’ll be free at last (and should be able to finish a draft of my next book by January 15). Forward march.