The concept of the bifilm is now about 15 years old. The realization of its influence in metals has significantly advanced over these years. It has been clearly shown to control structural defects such as porosity and hot tearing, plus mechanical properties such as ductility and fatigue. It appears to explain for the first time the structure of Al-Si alloys and cast irons. Furthermore, it appears to be the only crack initiating feature in metals, thereby constituting the only source of Griffith cracks. Thus it has control over crack initiation for metals. As a result, it seems that failure by fatigue and creep may be eliminated, together with invasive corrosion such as pitting, stress corrosion cracking and possibly other failure modes. The elimination of bifilms by improved melting and casting methods appears to be possible, and would deliver metals of extraordinary properties not seen so far.