I like to save important stuff to a big USB drive that I isolate by physically unplugging from the computer. This would be a good option for safeguarding your book. I also prefer to save everything to a second physical hard drive on the computer, they are easy to add. The drive with the operating system is much more volatile than a secondary drive.

--

What drives me crazy is the "Response Window" on Medium. Often in the middle of typing a longish response (like this one)...zap the entire thing disappears, I'm kicked off the site and I have to navigate back and start over. Drives me nuts. Plus it's happened on more than one machine, so it's not my computer.