hmm... tl;dr anyone? I wanted to like this, but am finding it rather confusing and unstructured so far.
That said, the nonlinear part: picks out every now and again a pop culture echo of the current theory being discussed, like the Terminator or the Time Machine or Heinlein's "—All You Zombies—" i.e. the one where a person is their own mother, father, son and daughter. (I really wish it talked about Looper or 11/22/63 or Rick & Morty.)
Discusses whether time travel is logically possible, how paradoxes could ever work, causality - the overall tone being time travel is basically impossible as we know it but boy is it ever fun to think about.
Edit: for those downvoting, the article linked is actually a pretty good introduction on why time travel may be self evidently impossible through simple logic (we already know the event didn't happen, so it can't go back and happen), but also may be self-evidently possible if certain criteria is met first (specific fuckery involving time-like closed loops and multiverse theory, which means, essentially, history can't be trusted or multiple concurrent histories can't be trusted, respectively).
So, yes, it is confusing to need to think about logic in the terms presented by the article.