I won't rate this one because I feel the preceding book How Can Man Die Better: The Secrets of Isandlwana Revealed has to be read before this one, or at least another book on the wider context of the Zulu war, to really appreciate this account. I have read on Rorke's Drift and the Zulu War before, but not in a while and so the immediate context of the battle (the earlier Isandlwana and both battles' importance to the war in general) was not apparent; while most books would provide the reader with a brief introduction to the war and the build-up to the battle, as the historian has covered this in How Can Man Die Better, in this account we get no context. Not a problem if you're well-versed in the Zulu war, but I couldn't properly get into this. Still it was as good read, I bought it from a charity shop hence not realising the importance of the preceding book, as a standalone read it covers its topic very well (though I prefer my battle books to discuss context much more than this one does), what it really is, is a bash-by-bash account of the defence of Rorke's Drift, going so far as to tell you exactly what happens at any given minute (as far as sources allow), what rooms the soldiers occupy and when they leave it, which key figures are involved and when they die, etc.
It goes into such a granular detail that I have never read before in a book focusing on one battle - your average Waterloo book for instance may well zoom in on the punchout at La Haye Sainte for a time, but cannot afford to give in pages what Snook does here. Probably because, when all you focus on is this battle, it is not a particularly complicated affair: at its most basic, it's a load of red coats stuck in a barn, shooting and bayoneting waves of dudes. Hence why it is so popular as a story of bravery and bloody warfare. Snook captures this element of the battle brilliantly, making his empathy for the 24th regiment and its brave enemies clear throughout. At the same time, its greatest flaw for me was the name dropping which at times was too much - in trying to showcase the individual bravery of the regiment, the book overloads us with names. Without knowing the significance of any one individual over the other, it's hard to know what to focus on. That said I did enjoy the historian's passion for telling the soldiers' story, even listing all their names at the back of the book. It feels like a book written out of passion, and by a soldier too - who understands the battle through the footsoldier's perspective more than your average historian. The drawback to that is this book is very matter-of-fact, and as mentioned tends to labour the smallest details a bit too much.
As a source on the battle singularly (which is what it sets out to do), you probably won't get any better. The detail is immense and Snook is careful to debate the sources within the text, determining fact from fiction as much as he is able. I loved the diagrams, literally drawing a picture of the hospital + storehouse, its defences, and (as the battle develops) the relative positions of the Zulus/defenders. There's 20+ pages of coloured pictures as well, contemporary paintings of the war and modern photos of Rorke's Drift today. It makes the battle incredibly easy to visualise. If you desire focusing specifically on the battle and nothing else, I would recommend this.