What it sets out to do
The original Hunger Games trilogy gave us President Snow as an established monster. This book asks a harder question: how did he get there? Following a teenage Coriolanus Snow, privileged but precarious, brilliant but hollow, through his time as a mentor in the 10th Hunger Games, Collins traces the moral compromises that compound into something irreversible.
It's an uncomfortable book to read because Collins makes you understand Snow. Not sympathise, exactly, but understand the internal logic that leads from each small betrayal to the next. By the time the ending arrives, you don't need to be told who he's becoming. You've watched it happen from the inside.
The uncomfortable protagonist problem
This is also the thing that will put some readers off. Spending hundreds of pages in Snow's perspective requires sitting with someone whose values are corroding in real time. The book doesn't make it easy by giving him redemptive qualities that matter: his occasional warmth is always conditional, always in service of himself.
Collins doesn't write villains. She writes people who make villain-shaped decisions, and shows you the reasoning.
That's more interesting and more disquieting than a character who is simply evil. But it does make for a different reading experience than the original trilogy, where Katniss gives you a clear moral centre to anchor to. Snow's narration has no such anchor.
Lucy Gray
The tribute Snow mentors, Lucy Gray Baird, is the most interesting character in the book and functions almost as Snow's mirror image: someone who also performs for survival, but with genuine warmth and creativity underneath. Their relationship is the novel's engine, and Collins uses it well to show what Snow could have been and chooses not to be.
Lucy Gray also connects the world to the original trilogy in ways I found genuinely satisfying: the songs, the mockingjay symbolism, the roots of the Districts' resistance culture.
Compared to Sunrise on the Reaping
I read this before Sunrise on the Reaping, and I think that's the right order. Songbirds and Snakes is the more intellectual of the two prequels: it's a book about ideology and self-deception. Sunrise is more viscerally emotional. Both are worth reading, but Sunrise hit harder, possibly because Collins has refined what she's doing here.
Four stars rather than five mainly because the pacing in the first half is uneven and some of the Capitol sequences drag. The final third is excellent and earns the book its place in the Hunger Games canon.