A burner which is capable of producing zero NOx and zero CO by passing a thoroughly mixed stream of air and fuel at an appropriate air-to-fuel ratio to maintain a temperature below the NOx forming threshold through a radiant combustion zone. The radiant combustion zone provides the intense radiant energy required to initiate and to complete the combustion process. The burner comprises an Air-Fuel Ratio Attainment Means (AFRAM) and an Air-Fuel Mixing Means (AFMM) in fluid communication with the AFRAM to thoroughly mix the air and fuel to provide a readily combustible mixture, and one or more Radiant Combustion Zone (RCZ), and a Combustion Initiation Means (CIM) located in a combustion-initiation-contact position to initiate the combustion in the RCZ. A high velocity section or a porous flow permeable membrane is used as a combustion guard to prevent flameback from occurring. A second porous flow permeable membrane may be used as a flame trap for containing the infrared radiation within the radiant combustion zone. The burner can be used in commercial and domestic appliances and space heaters. At lower excess air the burner can be operated as an ultra low NOx burner.