Here's where Star Trek all began: The adventures of Captain April and the crew of the USS Yorktown!
The TOS series bible is reproduced in The Making of Star Trek
. I've got the TNG, DS9 and VOY ones as PDF files, although I don't recall where I got them from. There's also a wealth of early Voyager concept info in A Vision of the Future: Star Trek Voyager
. Ditto DS9 in The Making of Deep Space Nine
The novelization of "Broken Bow" has an added section about the design of the show, but IIRC it focuses more on things like set design than character/universe concepts. There's an early character bio sheet from when they were casting out there somewhere in cyber space, starring Captain Jackson Archer, first officer T'Pau, Starfleet Marine Malcolm Reed and the engineer, Spike Tucker.