In the Metamorphisis, Kafka explores philosophical absurdity, surrealism, and alienation.
The reason for its inclusion in this part of the map (under the branch concerning identity and the body) may seem obvious.
But the about the relation between our bodies and our identities is made more complicated—not less—by his protagonist's transformation from man to insect.
Kafka could certainly be placed in the branches concerning reality, existence, and the nature of thought—his emphasis is certainly on consciousness, but it's a guiding text for this course because of its focus on the body first.