Red Nails is about the futility of war. The Tlazitlans dwell in the ancient lost city of Xuchotl. Howard makes the point that for them the city is the whole world, a world they have turned into a perpetual battleground. When they first came to the city they gained entrance by means of deception: A slave in the city let them secretly in, and they quickly overcame the weak and ill-organized defenders. After centuries of inhabiting the city, the descendants of its builders had shrunk in numbers and had lost the knowledge of the ancient magic that had protected the city. Those who were not killed by the Tlazitlans were tortured to death by the vengeful slave Tolkemec, who had let the invaders in.

The city of Xuchotl is a wondrous place, with some corridors illuminated by glowing jewels and others always in darkness. Treasure in...