Btukfyl

A friend lent me an interesting book in about 1985 that was a fictional history of spaceflight from 2000-2100. It was a largish book, with full-color full-page graphics, with only a couple paragraphs of explanitory notes per page. It covered our contact with Alpha Centauri, the development of various spaceflight technologies like new engines, and new spaceships developed for certain wars which happened. The last half-dozen or so pages were dedicated to alien derelict spacecraft that we had come across, and the mysteries surrounding them. I remember that one of the derelict alien spacecraft was organic, and another one was semi-transparent like a 3-d hologram.

The book did not seem old-fashioned at the time, so I would guess it was from the early 1980's perhaps. In other words, it definitely wasn't 60's- or early 70's-era art or concepts.

Unfortunately I don't remember the name, author, or much of any wording from inside, other than our first contact being with a civilization from Alpha Centauri.

This is almost definitely "Spacecraft 2000 to 2100 AD" (a "Terran Trade Authority Handbook" - wiki link)

The "semi-transparent" ship is probably "Object #1 at Barnard's Star" (art by Tony Roberts).

Edited to add:
I think I've finally found the other image you mention, also by Tony Roberts: