|quote = '''''"Thought Begets Doubt, Doubt Begets Heresy and Heresy Begets Retribution."'''''<br>''- Codex Imperialis''{{Fn|2}}

The '''{{PAGENAME}}''' is a new [[Imperial]] document being written by [[Roboute Guilliman]] in early [[M42]]. Unlike the [[Codex Astartes]] which focused purely on military organizationorganisation, the Codex Imperialis will be largely a civic document focusing on the reorganization reorganisation of Imperial government. In addition, it will include the first reliable history of the Imperium in 10,000 years.{{Fn|1}}