Adding book blerb to file

With the more recent versions of Calibre, I find that, when I edit the MetaData and add in the book's description/blerb (the information that usually is on the back of the book), it doesn't always appear.

Usually, it appears soon after the title page of the book but is missing in some books.

Is there a way this information can be added to the epub output file that I'm creating?

Thank you.