When I was considering doing my book, Eric (Jackill) was kind enough to give me his number and we had a nice conversation about Trek tech publishing. I was gobsmacked to hear that he made enough money to put himself thru college with the Jackill publications! Meanwhile, my book has been out since 2017 and I think I've sold, maybe, a couple hundred. Oh well.

Timing is everything. Back then (the 90's), Trek publications were at their peak, including tech-related manuals and reference materials, art books, etc. Hell, IIRC, the Okuda's were publishing updates to their Star Trek Encyclopedia every other year back then and they were best-sellers. Nowadays, there really isn't the market for it as much anymore. A few of us old main-stays from that time still pull in anything we can find like that, but it definitely isn't the draw that it used to be, more's the pity...

It's working for me.