The modern concept of ”diagenesis“ was introduced by Walther one hundred years ago to encompass the postdepositional processes that affect sediments from deposition to low‐grade metamorphism. Since Walther (1893), diagenetic studies have been concerned with an extraordinary variety of chemical and physical interactions, each of which has the potential to significantly affect the final composition and texture of a sedimentary rock. The issues to which those studies have been applied are equally varied and include: (1) improved techniques to predict the producibility of hydrocarbon reservoirs, (2) improved techniques to predict subsurface fluid pressures, (3) better constraints on the timing of fluid flow events, (4) reconstruction of global climate change, and (5) evaluation of groundwater contamination. Commercial applications of diagenetic studies have traditionally focused on the producibility of hydrocarbon reservoirs. As such, a review of this topic serves as an effective illustration of how basic research has been commercialized, and a useful focus for the following dicussion. However, it is worth noting that decreased industrial research funding, coupled with increased government funding for environmental research have recently resulted in a gradual evolution of diagenetic publications away from the producibility of hydrocarbon reservoirs toward the producibility of uncontaminated groundwater and other environmental issues. Despite the shift in emphasis, many of the basic research issues remain unchanged whether one is focused on deep hydrocarbon reservoirs or shallow aquifers.