Saucer Attack! is a 1997 book with great graphics, showing the first half century of flying saucer pop culture. There are dozens, if not hundreds of book covers. It's usually available on eBay, and I've seen some copies on Amazon.com, but buyer beware: prices are all over the map when you shop for this out-of-print book.
I've tried not to duplicate what has already been shown in Saucer Attack! when showing some of the covers I have of saucer books.
Saucer: the Conquest by Stephen Coonts is from 2004, and it's in the thriller vein: a 140,000-year-old saucer is dug up and of course it still works. Those aliens may be dumb enough to forget where it's buried, but at least the battery didn't lose its charge. It's the second book in the series.
This could be one of the rarest books I own, found at a thrift store. It's a hardcover edition of The Hollow Earth, a cranky 1964 book by Robert Bernard, Ph.D, who claims flying saucers come from the hollow core of the earth, accessible through a hole near the North Pole.More later! Ciao for now.