Another Good Will find recently is the Star Trek Concordance Bjo Trimble. Before the Star Trek Encyclopedia came out this was the way to go for all things Trek and in a way still is.
The black & white illustrations have a Star Trek Fan based quality to them adding a DYI old school feel to the book & it sets up the OSR mood of the book nicely for me.
How & And Why It Works As a Resource
There have always been differences between Fasa & regular Trek shows. These gaps aren't so much a hindrance to a DM as an opportunity for bridging the gap with a PC driven adventure. For many years the various Trek "authorities" have dismissed the Animated series for example. But the fans have know better & used that opportunity to expand into the worlds that many authors dismissed.
The most important thing about Trek is its accessibility & recognition The Concordance enables a DM to instantly, completely, & simply grasp a Trek concept & make it their own. Everything is broken down to its simplest essence enabling the DM to not get lost in the minutiae of Trek.
This book could be used to create a "Keep On the Borderlands" style adventure any number of games while keeping that oh so instantly recognizable Trek brand. Need a item, a phaser, a whole alien species for a game? Bang their right in here. This is a very non game source for lots & lots of ideas as well to fill in those campaign background pieces
This makes the Concordance something that I'm still reaching for even before the slick production, etc of the Star Trek Encyclopedia. There is more of an intimacy & DYI sense of this book.
This Concordance makes it easy to live, work, & dream along with part of a Star Ship crew. This makes the book still matter to me all of these years.
I've since worn away & tattered my copy of the original Concordance pictured above!