As open war wages across the galaxy, the Imperium must guard its realms from the heretics and mutants that seek to corrupt and subvert from within. The Imperial Agents seek to hold them at bay. A loose coalition of Inquisitors from the Holy Ordos, swashbuckling Rogue Traders, and zealous priests, they command clandestine forces in an attempt to defend the Imperium against the most insidious threats. Codex: Imperial Agents contains background on the many distinct bodies that form their military forces, and provides rules using them as an full army in Warhammer 40,000, or as allies for other Imperial armies.