The Black Library is now selling copies of the Horus Heresy Promethean Sun hardcover.
From their website:
The Great Crusade reaches a feral world known only as One-Five-Four-Four. The forces of the Imperium arrive to deliver the primitive natives from enslavement at the hands of the alien eldar. The Iron Hands of Ferrus Manus and Mortarion’s Death Guard fight in theatres of war across the world, but the most vicious combat takes place in the deep jungles, where Vulkan and the Salamanders bring the Emperor’s wrath to the heathen aliens.
Vulkan and his sons must brave the deadly jungles, battle monstrous reptilian beasts and contend with the vile sorcery of the eldar if they are to liberate this world and bring the Emperor’s light to its backwards inhabitants.