Quofum by Alan Dean Foster. He's my favorite sci-fi author, which is great because he must crank out about six books a year. It's never "hard" sci-fi; the technology is never explained and just exists to make the stories possible.
This one is about a planet that appears to pop in and out of existence. A team is sent to explore it (who would volunteer for that mission???) and discovers that it is teeming with life, but the biology of the various lifeforms cannot possibly have evolved from the same source. It almost seems as if plants and animals from many different planets were just dumped there.
I'm waiting for it to blink out of existence and pop up in another galaxy (or universe, I wouldn't put it past him), with the team still there.
Most of his novels are somewhat light-hearted and full of humor, although this one isn't; there's already been a murder.
My all-time favorite is the Taken trilogy, just because it features an issue that has been rattling around in my head since I was a kid and back then when we all believed in aliens it actually gave me nightmares:
Suppose aliens came to earth, kidnapped you, and took you to their planet for nefarious purposes. (In this case humans--and one dog--are destined for private zoos.) The Good Guys from the other side of the galaxy have been chasing these Bad Guys for a long time and finally catch them, but in the process the Bad Guys' ship and the information in its computer is destroyed.
After being put up in hotels by the Good Guys and learning all about alien culture, you finally tell them, "I'd really like to go home now. Can you just take me back to Earth?"
The answer, "Of course, we'd be happy to!"
"Where is it?"
Talk about feeling alone in the universe! How many of you could give an alien space captain the vaguest directions to Earth?