1 The history behind the development of some of the fundamental concepts in the geosciences is truly fascinating. Some outstanding characters with brilliant insights have laid the foundations of our discipline. This history has a full cast of characters, and major advances have been made by drinking potions laced with ingenuity, serendipity and happenstance. Hypotheses have come and gone, great debates have raged. You all know Paul Hoffman as a researcher of the highest stature, and he has garnered a host of the most prestigious national and international awards for his research. Paul is also a passionate student and disciple of this history, and as is evident from his photograph, he has lived through many of them! He will contribute a column, aptly entitled Tooth of Time, to each issue of Geoscience Canada. His contribution to this issue is the first of many fascinating narratives of how major discoveries are made, the amazing characters to whom we owe so much, and the importance of mentorship as transformative ideas are handed from generation to generation.