This is one of those books that is impossible for me to describe. I almost set it aside as I wasn't getting into the characters and nothing was really happening. Then, around 17% in, the Primer showed up, all the plot lines converged and the story took off. After that, I couldn't put it down. Unfortunately, the last 10% or so lost me a bit. I didn't totally understood Hackworth's experience with the Drummers and Miranda disappeared from the story just when I thought she was going to be a big part. Things made more sense towards the end, then suddenly it all ended way too abruptly for me. I hate those type of abrupt endings--they seem all modern and cool but I am just left annoyed. Overall though, I really enjoyed the book so I have to give it 4 stars.