I have known Frank for forty years, starting when he took his first sabbatical from the University of Alberta and spent time at the University of Waterloo in 1978. I recall his goal was to learn a bit more about finite element modeling. At the time, I was midway through my Master’s degree in the Department of Earth Sciences. It was a timely visit as I was working on the analysis of the first natural-gradient tracer test I had conducted in the Borden aquifer. Frank had just published his classic 1977 paper in Water Resources Research entitled “Macroscopic dispersion in porous media: The controlling factors”. His insight was instrumental in interpreting the scale-dependent dispersion observed in the data. This led to the first paper I ever published in my career, and his advice encouraged me to continue to pursue studies of the role of physical and chemical heterogeneity on macrodispersion. A couple of years later, Frank, together with Les Smith, extended his original work on macrodispersion by taking a stochastic approach, including uncertainly analyses on contaminant plume evolution. These series of papers were published in WRR and represent one of the first efforts to quantify solute transport prediction uncertainty due to geologic heterogeneity. These works inspired me to continue my work at Borden by performing a geostatistical analysis of the subsurface heterogeneity at Borden and tying it to the observed macrodispersion from the Waterloo-Stanford tracer study, published in a series of papers in 1986. Frank’s work on mass transport in unconsolidated geologic media was soon after followed by a series of papers involving discretely-fractured media, a topic I was also interested in during my development of several analytical solutions describing transport in fractures, including the effects of matrix diffusion. In subsequent years, I have been honored to co-author several papers with Frank on wide-ranging topics. I always like to say that Frank is not just a smart hydrogeologist, but also a wise one who has mentored so many hydrogeologists over many decades.