At first this was a little bit difficult to listen to. I didn’t understand the beginning, but I plodded through it. In the latter part of the first half, I went back and re-listened to the first part of the book carefully. It isn’t so much a problem with boring content, it is a bit of a fire-hose of plot, characters and the physical world. It seems to be a lot to keep track of in the beginning , but it all comes together. And the excitement built from where it was putting me to sleep, till halfway through the book, it became quite engaging and I couldn’t wait to get back to it. The Book had a terrific second half. It kept me up at night until I finished it. It isn’t for younger readers. There is quite a bit of adult romance. But the time-travel military space battles were my favorite. The physics is interwoven with pre-destination, and the shape of the universe with existentialism. . I won’t give it away. I listen to audible books every night and every night they put me to sleep. With rare exception. This was one of the exceptions. In the end it has to be five stars because the ending was a surprise and it had me reaching for the sequel! It was Fun thought-provoking and engaging!