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Animal and human wastes are an increasing problem. Liquid and solid animal wastes, sewage sludge, and municipal solid wastes generate considerable gas and odor, harbor disease, and contribute to environmental problems. Because both animal confinement facilities and urban areas are growing in size, these effects are becoming more concentrated, with the result that millions of dollars are spent annually on storage, transport, and treatment of these wastes. Thermochemical conversion (TCC) instead uses high-liquid content wastes as an energy source. TCC is a group of chemical reforming processes in which organic matter is subjected to heat and pressure, typically in an anoxic or near-anoxic environment. Recent publicity surrounding the application of TCC to swine manure, offal, and other wastes has underlined the need for a full analysis of the large body of associated research. This paper provides the first comprehensive survey of the literature associated with TCC as applied to animal and human wastes for treatment and energy production. TCC research on system design, feedstocks, and resultant products is categorized, and advances in understanding of the underlying chemistry are reviewed. Finally, weaknesses in the body of knowledge and needs for further research are discussed.