Sounds like one of the Svetz series, probably Rainbow Mars.

If you want Niven at his most Hard-Science, check out The Integral Trees and The Smoke Ring. Humans on a STL starship had colonized one of the weirdest liveable environments in the universe, then fallen back to barbarism and forgotten their roots.

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"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
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Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
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