It used to be that I would see my list of bookmarks when I poked the bookmark icon. But now, all of a sudden< I no longer get my bookmarks but, instead, a screen labeled History. What have i done wrong?

What reading app are you using?

Afraid I don't understand your question. My settings are whatever the iPad came with; I have not changed anything. As I said, I am very green here.

Thanks all. I found the answer to my original question.
The screen that appears when I click the open book icon DOES show my bookmarks, AS WELL as my History. ThEre is an option button there I was not seeing.