I might be coming a little late to the ball on this one, but my copy of this only arrived yesterday, so I've only had a chance to read into this a little bit.

Spoilers, obviously!

As is always the case with Alan Bligh's stuff, though, it's excellent. He's been my favourite 40k writer for a while now, and this book is keeping up the high standard he set with the earlier HH FW books.

I've only read a few sections (the Iron Warriors, Alpha Legion and some of the Imperial Fists section) but a few fun things leap out immediately:-

• The link between the Iron Warriors and the Minotaurs seems to me to be more explicit all the time. I know this is a fan theory that's been rattling around for a while, but Mr Bligh seems intent upon dropping further hints to draw connections between the two. The similarities between their iconography, personality and methods, and their mutual admiration for ancient Greek culture seem more marked as a result of the content of this book.

• A really neat little section on the Alpha Legion reintroduces Alan Bligh's own nasty little xeno race, the Slaugth (they crop up across his work) in the context of the backstory of the Alpha Legion Primarch/s. Admittedly, this is in a story explicitly described as "a lie" but it is nevertheless an interesting take on the conflicting (deliberately conflicting) narratives surrounding the Alpha Legion

• One thing he's done which I really like is to imply that the Alpha Legion's cell structure model has become so successful that the majority of the Legion - even its high command - has no idea what the majority of its cells are up to. Given that this is advanced as a suggestion as to how the Legion operated in M30, one can imagine how confused the Legion's command structure has become as of M40. This is a very clever conceit, at a stroke giving an in-canon explanation for any discrepancies in the methods/allegiance/degree of chaos corruption encountered by different Alpha Legion units.

More as I read into it more! Any thoughts on the book from anyone else?

There are also some interesting nods to a number of Imperial Fist successor chapters in the iconography of that legion in the book. The whole thing is a treasure trove of Easter Eggs for long term fans: it's clearly intended to read as such.

Also a few hints as to the parent chapter of the Carcharodons hidden in the Raven Guard background

Also a few hints as to the parent chapter of the Carcharodons hidden in the Raven Guard background

Nuh Uh! I'm a huge space shark fan and I don't have this book so this is great news! Care to explain a little more about them for us?

sure

since all Astartes are from Terra the original Raven Guard was recruited from a nomadic tribe that used bone shrimshaws and stuff and had a very savage style of combat, rapid raides, extrem violent and rule of the strongest (which gave the Legion its informal name Pale Nomads or Dust Clad)

those became the original Raven Guard that were attached to the Sons of Horus (at that time still Lunar Wolves) since they were undernumbered somewhat and Horus treated them more like a company of his Legion than a seperat Legion

they actually worked great together since both employed rapid raids and tactics aimed at the heart of the enemy

when Corax was found and after the whole slave moon thing on Deliverance he stopped recuitment from Terra and mostly used recuits from his homeworld (in addition to some made on the way of course) which included many of his old rebel fighter buddies that favoured a much more subtle and covert style of fighting so the terrans and the original commander of the raven guard (Shade Lord Arkhas Fal)

Before the Istvaan Massacre the Terrans and Arkhas Fal had already been send of as "Predation Fleets" to the edge of the empire to hunt xenos and fight alongside Rogue Traders

there is a bit more details so i highly recommend the book (all Horus Heresy Forgeworld books actually)

There's a complete origin story for how the planet Necromunda joined the Imperium...