What I love most about this book is that the aliens are ALIEN. A lot of authors write aliens as humans with a coat of paint, or funny protuberances, but the biology - and hence, the philosophy - of the pequeninos is bizarre. That's where the central mystery of this book comes from. What made the tribe of pequeninos kill the anthropologist assigned to study them? It's a compelling mystery, and I really enjoyed how solving it revealed so much the characters and the world they live in.