here for the League period.
And here are two from a single day during the Empire period. First, Dominic Flandry's superior, Admiral Fenross, says:
"'If I didn't oblige the peerage,...I'd be begging my bread in Underground and someone would be in this office who'd never tell them no.'" (Sir Dominic Flandry, p. 192)
"...rhododendrons bloomed like cool fire in Terra's parks, and the laughing youth of Terra's aristocracy flew past on their way to some newly opened pleasure house." (p. 197)
Other Anderson sf novels, e.g., The Long Way Home and The Corridors Of Time, present high tech futures in which a large percentage of the population is permanently unemployed and either impoverished or minimally subsidized. This single reference to "...Underground..." implies a similar lowest social stratum in the Terran Empire although it does not tell us how many Undergrounders there are. Are they literally underground or does "Underground" just mean "the under-class"?
We are used to societies in which wealth is unequally distributed but this does seem to be an extreme case. An able individual like Fenross could be impoverished at the whim of a "peer" while at the same time youths who have done nothing to generate any wealth fly to a pleasure house even though Terra is now at war on two fronts.
"...when the bombs finally roared out of space, when the barbarians howled among smashed buildings and the smoke of burning books hid dead men in tattered bright uniforms - when the Long Night came, as it would, a century or a millennium hence, what difference? - something of beauty and gallantry would have departed the universe." (p. 190)
Maybe, but the Long Day will last much longer if more people have a stake in defending it. How many Undergrounders will join with extraterrestrial barbarians in smashing buildings, burning books and killing anyone wearing a uniform?