Recursion by Blake Crouch

I loved this book at the beginning.  I was into the characters, I was intrigued with the idea of trying to retrieve memories for people with Alzheimer disease, and it was fast-paced reading with lots of twists and turns.  However, I wasn't as fond of second half of the book.  I found the timelines harder to keep track of, and I wasn't as engaged with the characters.  I also found the science behind everything harder to grasp in the second half. I gave this 3 stars.