Neptune's Brood

Metahumans — engineered posthuman lineages — and an interstellar economy running on three tiers of debt.

Accountancy. Interstellar colonisation is financed by slow money that takes decades to clear, so the indispensable profession is forensic audit, and the protagonist chases a fraud across light years.

Manufactured scarcity — The abundance is real, so a new scarcity gets invented to compete over.

Funnier than it sounds, and the only work here where the surviving occupation is bookkeeping. Stross's argument is that debt outlives every other institution.