Every sphere of intellectual endeavour calls forth individuals who make it their task to assimilate, interpret and transmit an evolved understanding to those who may share their interests. This happens at many levels. Some may choose to address groups of specialists through the pages of learned journals or through professional conferences. Others, such as the many dedicated teachers everywhere who daily pass on the light of learning to their charges, work less visibly. And there are certain projective individuals who will skilfully make use of the dominant media, whether print or electronic, to transmit their message as widely as they can. A few seem to be capable of spanning all levels, thereby making substantive contributions to the collective understanding of their times.