The Line of Polity is a 2003 science fiction novel by Neal Asher. It is the second novel in the Gridlinked sequence. In this novel, Earth Central Security (ECS) agent Ian Cormac is placed at the center of a civil war on the planet Masada, where an elite Theocracy lives in cylindric habitats in orbit and violently rules over commoners enslaved to laborious agriculture jobs on the planet's surface. To complicate matters, someone has attacked a low-grav Outlinker habitat with a nanomycelium which bears a striking resemblance to that used by Dragon on Samarkand in the previous novel Gridlinked. Meanwhile, a brilliant Separatist biophysicist has apparently reactivated an extremely ancient relic of technology created by the Jain, an alien species that dropped out of the universe millions of years ago, and commanded forms of technology that the brightest AI minds of the Polity have difficulty comprehending.