Would a bubble wrap envelope be enough cushioning when sending a soft cover book?

Yup!

That should work. If in doubt just wrap the book in bubble wrap or newspaper before you put it in the envelope.

Yes, absolutely. I have sent books in (plain) manila envelopes as well, with no damage. But a bubble wrap will certainly do the job.

Yes.

Totally.

If I were being especially careful of the book, I’d wrap it in tissue paper first to keep the pages tightly closed. Then I’d make sure that it was snug inside the envelope so it didn’t slide around.

I’ve received many books this way and feel confident that they arrived in as good a condition as when they left the sender.

To be extra safe you could wrap it in brown paper; you can just use a paper bag from the grocery store and cut it up. Wrap like a Christmas gift and then put it in a bubble envelope.

My dad sells used books, that is his business, and he uses the bubble “bags” you slip the book in and fold it over and it has a sticky strip to seal it, and then he would fold over any excess on the side and tape it well, and then slip that in an envelope or box. But, he has all sorts of packing supplies since it is his business.