Charles Repenning was murdered in his home in Lakewood, Colorado, on 5 January 2005. He was 82 years old and, although retired from the United States Geological Survey (USGS) and battling several health issues, was still fully engaged in research activities as a paleontologist and biostratigrapher, and was maintaining a long history of running correspondence with his colleagues and family. He retained his wit, his intelligence, and his wealth of knowledge and ideas gathered throughout a long life that was, nonetheless, cut short all too soon.
As a professional scientist, his contributions to his chosen fields of study were numerous and continue to have an impact today. Although many of his ideas were controversial, he was a tenacious and capable opponent in a discussion or debate, both in print and in person. As many of the contributors to this volume attest, his discoveries and ideas continue to stimulate new research and to provide an intellectual context into which new discoveries can meaningfully be placed. Within his realm of interest, he had an encyclopedic knowledge of the temporal and spatial distribution of ancient organisms, their fossilized remains, and the geologic, climatic, and environmental contexts in which they evolved and were preserved. His long history with the Paleontology and Stratigraphy Branch of the USGS, and his deep engagement in the paleontology of the western United States, gave him a wealth of knowledge, much of which was unpublished or lost in the relative obscurity of contract and open-file reports. He had an uncanny ability to recall such reports and their contents and, when asked, would willingly provide assistance to others in accessing the material.
As our epigraph suggests, he maintained a strong interest in integrating multiple data sets to develop holistic approaches to paleontology and stratigraphy (Repenning, faxed letter to Christopher Bell, 7 July 1993, p. 4). Somewhat ironically, he occasionally was slow to accept and integrate new data as they emerged, and he was sometimes stubborn in his rejection of new concepts and ideas, especially if they challenged his methodological or philosophical approaches to his work.
In person he tended to be quite benign, and to maintain a humorous and engaging demeanor. But in his correspondence he could be gruff, aggressive, and abrasive in his dealings with other scientists, especially students. That off-putting behavior, combined with his tendency to remain entrenched in his private home office and his reticence later in life to attend scientific conferences, effectively denied many students the pleasure and challenge of getting to know him and learning from his insights and experiences. He was an extraordinary correspondent, capable of crafting long and complex responses even to simple questions. One of us (CJB) once wrote and asked him why he did not like a particular method of climatic reconstruction based on vertebrate fossils. His response, received by post four days later, was six pages of single-spaced text, ending dramatically with "I dare you to ask another question" (Repenning, letter to Christopher Bell, 18 June 1993, p. 6). In another letter he wrote "I'll bet you changed to larger type so your letter wouldn't look so short when compared to mine. You can't win, buddy, I've outpaged the best" (Repenning letter to Christopher Bell, 15 May 1995, p. 1).
Most people knew "Rep" from only one perspective and in one capacity. We consider ourselves fortunate to have become acquainted with the many facets of his personality. Members of the scientific community now are bereft of his company and will have to shape their opinions based only upon his published works and what remains of his correspondence. Both of those sources will bear fruitful insights, but as a supplement to those we provide here a brief sketch of his personal history, with some anecdotes and reflections that we hope will help reveal some of the complexities that others never came to know.