Earlier quoted context omitted.
I wrote one on how to use an opensource testing tool for which there was lots of interest but not a lot of documentation at the time. That was quite popular for a while (almost 11 years ago). Another book was on an emerging technique for collaborative analysis for software projects, that started becoming popular some time back in 2008-9 but was still not well understood. Two more were on practical tips for how to wor…
Interesting. If you don't mind saying, do you self-publish on sites like Gumroad, Leanpub, Softcover, on your own site, or both? If on your own site, you would need some system to accept payments, right?
I used to sell books on my own site as well until a few years back when EU created the stupid VAT on private electronic purchases that requires stores to adjust price according to the country of the buyer. I figured it's less hassle to just use leanpub for that.