Complex sentence: The fictional universe of "The Hitchhiker's Guide to the Galaxy" series by Douglas Adams is a galaxy-spanning society of interacting extraterrestrial cultures, so the technological level in the series is highly advanced, though often unreliable.
Split into simpler sentences: The fictional universe of "The Hitchhiker's Guide to the Galaxy" series by Douglas Adams is a galaxy-spanning society of interacting extraterrestrial cultures. The technological level in the series is highly advanced, though often unreliable.