Books of Aliens and Monsters?

[prism]

A long time ago I remember seeing a couple books in a bookstore that were basically illustrated dictionaries of the author's imagined aliens and monsters (each had their own separate book). The illustrations were definitely pre-90s. Anyone have any idea what these books are? I didn't have any luck finding them on Amazon. I just remember these and am curious about them because they had really interesting artwork. Yes I'm a nerd.

 

[theflyingpig]

Yes I'm a nerd.

Oh, but of course you are.

 

[GodlessAstronomer]

You're welcome.

 

[Bignate603]

You're welcome.

Thanks, that will give me nightmares for the next month.