The Siege of Terra is a 14-book series with 11 released primary works first released in 2019 with contributions by John French, Guy Haley, Gav Thorpe, Graham McNeill, Dan Abnett, Chris Wraight, Aaron Dembski-Bowden, and James Swallow.
Following the 54th 'Horus Heresy' novel 'The Buried Dagger' the series was rebranded under the 'The Horus Heresy: Siege of Terra' label. Siege of Terra is the continuation of the story that began with the Horus Heresy series. The Siege of Terra is the finale of the overall Horus Heresy story and is set during the events of the Battle of Terra.
The series was followed by the 'Scouring' series.