Lagrange points are a key plot device in Iain M. Banks’s The Algebraist. I did figure out the location of the Dweller wormhole pretty quickly, thanks to thinkin

Lagrange points are a key plot device in Iain M. Banks’s The Algebraist. I did figure out the location of the Dweller wormhole pretty quickly, thanks to thinking about how Lagrange points worked, but it is a great work of science fiction.