Fuzzy Ergo Sum is a 2011 science fiction novel by Wolfgang Diehr as a sequel to H. Beam Piper's Fuzzy trilogy: Little Fuzzy, Fuzzy Sapiens, and Fuzzies and Other People. The trilogy concerns the discovery of a primitive species of small, childlike but sapient furry creatures on Zarathustra, a frontier planet with valuable mineral deposits, and the subsequent conflicts this generates between the Fuzzies, the humans who befriend them, and those who would exploit the Fuzzies and their land. Fuzzy Ergo Sum begins shortly after the conclusion of the trilogy, involving characters from those books in further adventures and conflicts. The story ends in a cliffhanger, and is concluded in Diehr's Caveat Fuzzy.
