Studies of the critical heat flux (CHF) carried out during the last decade have been reviewed, with emphasis on the main current of investigation flowing steadily toward a better and "unmysterious" understanding of the CHF phenomenon, together with a survey of a number of fundamental studies on the CHF. In order to attain this objective and, at the same time, provide a clear map of this field, the materials have been classified into four main boiling modes, subdivided into individual important topics and arranged in a proper sequence so as to show the synthetic framework of the CHF phenomenon, not as a mere accumulation of unrelated knowledge but as an organic combination.