I don't have a single book, but rather a series, The Chronicles of St. Mary's

Its a time travel series that takes place in what is possibly the near future with an amazingly well written protagonist and lots of twists and turns.

My partner started reading it a while back, and it seemed ridiculous when she explained it, but when my reading list was empty I gave it a try and I'm hooked.

I started reading in January, and am completely caught up, waiting for the next short story to be released.