Microwave heating offers a uniform, rapid, instantaneous, controllable and tuneable method for heating materials and thereby initiating chemical conversions. From the wide range of examples the almost universal appeal of this method can be observed. The major flaws of microwave heating have been turned to advantages. Limited penetration means small continuous reactors can be employed, thereby minimising the inventory of active material means a safer system. The relatively high energy cost is offset by cleaner products in higher yields and in some cases products that could not otherwise be observed.