We thank the editors of this special issue for their patience and encouragement. We are grateful to the Director Generals and numerous colleagues from the Geological Survey of Pakistan who have supported our research over many decades, and to the many people who have participated, willingly and with good humor, in the biostratigraphic surveys. The manuscript benefited from careful readings by R. Rogers and an anonymous reviewer. Fieldwork in the Siwaliks has been funded by several agencies, including the Smithsonian’s Foreign Currency Program (SFCP 7087120000-6) and the National Science Foundation (BNS 84-17903). Most of all we thank Will, who is still pushing us to produce more and better Siwalik research.