Captive universe is a rather short novel about an Aztec young man whose restless and inquisitive spirit makes him dare to deny tradition and fears and start discovering the real world around him. What he discovers is something he could never have imagined or believed.... but we, readers, must have expected just by looking at the front cover! And that is my first major complaint of the novel! Maybe this would have had more of a kick if I didn't already know what's going on.. but we are being shown and told before we even start reading. Actually it's very hard to talk about this novel without spoilers but I will do my best.
Complaint no 2 is of course plot and character development, which is a big mess and totally absolutely unbelievable... in a bad way! At one point in the book, a certain person has hardly seen a tool made of metal or a wheel before and lo and behold! a few hours/days later he can fix a huge air-purification or air-conditioning system just by a quick glance in a few minutes or explain cosmological and geophysical differences based on centrifugal forces vs gravity or understand the nature of hospitable planets and solar systems... and you get my meaning! Other characters also display the same incontinuity of personality and mentality which is a rather poor feat if we take into account that the number of all the main and secondary characters is not even half a dozen.
Complaint no 3 is that Harry Harrison is not that great of a writer. He's not bad but he will not excite with his wordcraft either. As I always focus a lot more on dialogue than descriptions, I thought his dialogues were rather rough, forced and not very realistic.
Maybe my expectations were higher that they should have been but I felt disappointed by this book. I can't really recommend it.