The discovery of the Long Earth awakens humanity's ancient desire for exploration. People of all kinds are drawn to these new worlds: adventurers, pioneers, dropouts, and dreamers, attracted by the pristine nature and unlimited possibilities of a new life away from the overcrowded and troubled Earth.

Technological progress brings dangers as the development of the Long Earth leads to conflicts and exploitation. Resources are plundered, and questions arise about the rights of 'others' - the non-human inhabitants of the Long Earth. The novel questions whether humanity can learn from its mistakes or is doomed to repeat them.

The encounter with infinite possibilities and one's own insignificance in the face of the Long Earth's vastness confronts protagonists with existential questions about human identity and purpose in a world of infinite versions of oneself.