This review paper considers the many techniques that have been developed to enhance convective heat transfer. A summary is given of the techniques that are effective for the various modes of heat transfer. Of particular interest currently is compound enhancement that involves the simultaneous application of several techniques, so as to produce an enhancement that is larger than the individual techniques operating separately. There are many experimental and analytical challenges that relate to obtaining and applying data. The current advanced enhancement represents 3rd generation heat transfer technology. This technology will find increasing application in all industries.