Uncharacteristically light on sensawunda for a Culture novel, The Hydrogen Sonata is still a solid installment in the Culture canon. A group of Mind super-sleuths reminiscent of the Interesting Times Gang from Banks' Excession is responsible for much of what I found enjoyable about the book. Additionally, the Mistake Not... and its avatar Berdle are satisfyingly interesting (to the reader) escorts for our main human protagonist. A few enjoyable space and planet-side battles allowed for the occasional high-Culture-tech fix, and a healthy dose of "which is more me, myself or a clone of my current mind-state" continues with the themes touched on but not quite as acknowledged in the previous Culture novel, Surface Detail.