YA Sci Fi. Space. Art of Roman gods with their planet, art of possible aliens, such as blimp like creatures on Jupiter or metal eating toads on Venus. Large soft cover book. Read in late 1980s.

[Thomas]

Please help!

[Kris]

Thomas, what happens near the start of the book? Who are the main characters?

[Ky]

There might not be anything happening in this book, Kris. It could be an encyclopedia. Thomas, is it an encyclopedia or is there a plot and characters?

If it is an encyclopedia, does the name Wayne Barlowe ring a bell at all? He did books like Barlowe's Guide to Extraterrestrials: Great Aliens from Science Fiction Literature and Barlowe's Guide to Fantasy: Great Heroes and Bizarre Beings from Imaginative Literature. I don't remember him illustrating anything about Roman gods but I haven't read all of his books, only the Guide to Extraterrestrials. But his art style may jog your recall.

Also there is a Alien Species wiki on the Fandom wiki. This site won't allow me to link to it directly but I thought I'd mention it if you want to try looking through it for your aliens.