A couple of weeks ago I said that I'd completed the Preface, after a huge amount (literally years) of trying to do so.
Sadly, it appears I spoke too soon. For not the first time in my writing career, Scott Meyers has sagely reminded me that I have a tragic tendency to conflate my introductory materials. So I've now printed Scott's essential gnome, along with a few other motivational items, and stuck it on the shelf directly above my right-hand screen.
So, lest I forget:
I'm now reworking the much-trumpted Preface into an introduction, and am writing a new, small, simple, on-point Preface.
Hopefully this one won't take five years ...