interworld

Interworld is a term used in speculative fiction to describe networks or interactions between multiple worlds or dimensions. In fiction, interworlds are typically parallel universes that characters can visit through portals, special abilities, or advanced technology. The concept allows exploration of identity, choice, and moral dilemmas across different versions of a person or society.

One prominent usage is the 2007 novel InterWorld by Neil Gaiman and Michael Reaves. The book follows a teenager who discovers he can travel between parallel Earths and becomes involved with a cross-reality organization that operates across the multiverse, navigating conflicts among rival factions.

Beyond this specific title, interworld concepts appear in various media—comics, television, and games—where protagonists encounter alternate timelines, alternate histories, or different manifestations of reality. The term is often used interchangeably with or as a subset of multiverse or parallel-universe storytelling.

In science and philosophy, interworld is not a formal scientific term; modern physics typically discusses the multiverse, parallel universes, or higher-dimensional spaces. Speculative discussions about interworld travel usually rely on fictional mechanisms such as wormholes, quantum branching, or magical gateways. The idea remains a popular narrative device for examining how small changes in one world might ripple into others, and for contemplating questions of fate, identity, and responsibility across many possible selves.

See also: parallel universes, multiverse, interdimensional travel.