A burner for burning fuels and modular heat utilizing appliances therefor. The burner includes a fuel holder, an outer wall surrounding the fuel holder and defining a combustion chamber, and optionally, a second wall surrounding the outer wall. Air is inducted from an inlet which may be an ash pan pivotally coupled to the outer wall at the bottom to open the combustion chamber. Supplementary combustion air is conducted to just above the fuel holder by the outer wall. Additional supplementary combustion air is conducted to just above the fuel holder by the second wall. The burner may include a pivotally mounted cooking grate and a pivotally mounted solid cover for closing the combustion chamber, and supporting legs. Modules individually yet replaceably attachable to the burner include a closed or open cooker, a smoker, a space heater, and a pyrolyzer.