There is 'speculation' that he will run for president again. [=some people think that he might run for president again]
The book is just a lot of idle 'speculation' about the future.
Her 'speculations' leave many questions unanswered.
(..) If you're having dinner, stop having dinner. Because you are going to want to witness this tonight. There has been rampant speculation about what really happened in the Quarter Quell. And here to shed a little light on the subject for us is a very special guest. that when you're in the Games (..)2014 The Hunger Games: Mockingjay - Part 1