On a quick trip to Washington, DC, I visited Kramer Books (of course). Apart for some loot for M, I got a delightful book on the history of the square root of -1 by Paul J. Nahin. I simply had to devour the first three chapters as fast as I could and am looking forward to finding the time to swallow the rest of the book real soon. I also have Dr. Euler’s Fabulous Formula by Nahin waiting to be finished; the two go together quite well, although I started with the Euler one, rather anachronistically. Apart from having massive amounts of fun reading this stuff, I am learning a good deal that I ought to already know about complex numbers. Really fabulous stuff.