The listing, Agatha Christie - By the Pricking of My Thumbs has ended.
Note: image does not really accurately picture this edition.
This is the 1985 Pocket Books edition of this book. It is pretty well used. The cover (front and back) is bent and creased. The pages look to be in pretty decent shape (a little bent and quite yellow).
Still, this is a great little book featuring the Queen of Mystery's married detectives Tommy and Tuppence.
Here's a description of the storyline (from Amazon):
'Ladies disappearing from homes of rest, sinister empty houses, hints of gang-leaders mixed with black magic -- mystery at the usual high Christie level.