At the library, the bookstore, we wander around the shelves until a book catches our fancy. Our first impulse? Flip it over, and read the synopsis.

But sometimes, we'll pick up a book from a series, often unintentionally. It'll confuse us slightly cause it's not the first book, and potentially spoil some things about the earlier book(s); though we won't understand these references (yet) as we haven't read the first book(s).

And so I ask you: how much should book synopsises reveal? With books in series I'm not as familiar with, I'll often turn to the back cover as both a reminder of what the books are about and details about what happened in the last book.

Instinctively I know that the back cover will contain details of the prior book if applicable, and so I wonder: should they contain these spoilers, or not? I've contemplated this question so many times, it's pretty old now.

Do you think book synopsises from books in a series should reveal details from the prior books?