Agent of Vega is a science fiction novel by James H. Schmitz, 1960. Like the
Foundation series, it is a collection of stories that originally appeared
separately in magazines. It was republished in 2001 as Agent of Vega & Other
Stories.
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In the far future, humans are building a 'Confederacy of Vega' to replace the
original fallen Empire of Earth. The new empire includes some mutated humans
and also some non-humans. Enemies are also a mix of humans and aliens and it is
very much space opera, featuring Vega's 'zone agents'. Combat involves both
physical weapons and telepathic attacks. It clearly owes a lot to E. E. Smith's
Lensman series.