There’s one past A-to-Z essay for the letter e that’s compelling after I looked at the exponential function on Thursday. That would be the number that’s the base of the natural logarithm. It’s a number that was barely mentioned in that piece, because I ended up not needing it.
But a couple years ago I wrote a piece that was all e, including points like how curious a number it is. I hope that you enjoy that piece too.