Black Library have just announced the release of The Scripts: Volume One. This hardback contains:
"...the complete production scripts for the first six Horus Heresy audio dramas – ‘The Dark King’, ‘The Lightning Tower’, ‘Raven’s Flight’, ‘Garro: Oath of Moment’, ‘Garro: Legion of One’ and ‘Butcher’s Nails’. With full soundtrack direction, character notes, and an exclusive introduction from editor Christian Dunn..."
I'd rather listen to them, but as you like. There a short video accompanying the release