Olaf Stapledon explores IQ power levels through world building and I find it interesting how different cognitive levels interact in a world.

- Sirius shows how a dog feels as it wades through the boundary between human intelligence and animal intelligence

- Odd John shows how a group of extraordinary people engaging in a world with normal people

- Last and First men show the IQ power levels of an entire system of "humans" progressing through stages of mankind

- Star Maker is the grand culmination where the entire spirit of the cosmos reaches the highest cognitive state and meets its maker thereby