When did it become common for books to have a summary on their dust jackets/ on the inside of their covers?

I was recently exploring my university's library and looked through some of the books and noticed how many of the novels and fiction books written and printed just a few decades ago had no description/summary in them.

As a member of gen z, it's very difficult for me to imagine trying to figure out what a books about and whether it's of interest without some kind of summary or description or the ability to easily do research to figure it out.

It got me wondering: is having a summary in a book a new phenomenon? How recent? Am I just going crazy?