I'm currently reading the Horus Heresy series in order, having just finished Nemesis (which after a disappointing start turned into quite a corker, and I almost forgot that Horus wouldn't be bumped off at the end). BUT I don't know what to go for next. I missed out Descent of Angels based on reviews and did the same with Battle for the Abyss, but after mentions of the Abyss in Nemesis and the books about Calth on the horizon I'm wondering whether to go back and read it? And if not, whether Tales of Heresy is worth checking out instead? Otherwise it's on to The First Heretic.