It is a great pleasure to prepare this citation honoring Jon Claerbout on the occasion of his receiving the Medal Award of the Society of Exploration Geophysicists. That he is achieving such a distinction in his mid-thirties comes as no surprise to those of us who have been fortunate enough either to have known Jon or to have followed his work for many years. Probably his first major technical project was his M.Sc. thesis on the subject of the filtering of geophysical data and of the important properties and characteristics associated specifically with minimum-phase filters. This thesis was particularly impressive on two counts! First, the technical material indicated a considerable capability to investigate and understand a complex subject; and second, perhaps more important, was the clarity with which this understanding was exposed and shared with the reader. It was apparent that here was a man of much ability who could eventually make a notable impact on geophysics.
     Some other uncommon qualities which Jon possessed were soon made clear. Some time ago, via some forgotten route of communication, I learned that following a year of study at the University of Uppsala he was now on a motorcycle somewhere between Sweden and Singapore. He was obviously intent on not giving all his interest to geophysics but wanted to see and learn about the world, with all its variety and peoples, through his own eyes. This unknown Jon Claerbout was becoming even more interesting.
     The next recollection I have of Jon was back in the geophysical domain with a paper in Geophysics on the subject of multichannel prediction error filtering applied to data from earthquakes and large explosions. Its content and clarity of exposition established that Jon's initial promise had in no way deteriorated and hence I was doubly pleased to meet him personally, for the first time, in the mid-1960s. Soon after this he joined the faculty at Stanford University and also became a consultant to the research subsidiary of Standard Oil Company of California. It was then that I had the first real opportunity to spend significant lengths of time both talking and working with Jon and helping introduce him to the challenge and joys of exploration. Fortunately for this Society, Jon became quite excited by the problems inherent in exploration seismology. At the same time he appreciated the satisfaction of sharing his knowledge and stimulating his students at Stanford.
     He has organized excellent summer courses at Stanford University on Time Series Analysis and Seismic Wave Propagation. His publications, and those co-authored with his students, on the application of the wave equation to seismic data processing have been imaginative and revolutionary, leading to an excellent practical method of migrating seismic data. His oral presentations at the Annual Meetings of the Society have introduced us to new technology and have been delivered to us with eloquence, delightful humor, and on those beautifully unorthodox slides of chalkings on a blackboard. No wonder that he received the best presentation award to last year's Research Session.
     Jon Claerbout's latest aid to exploration has been yet another unique venture, from which we can anticipate the benefit of new data processing techniques, together with students aware of the challenges of exploration. Approximately twenty oil companies and exploration contractors are now financing an Exploration Research Program to be directed by Jon at Stanford University. In spite of all this activity, he still managed to squeeze in a one year sabbatical at Princeton and the University of Sydney.
     The Society is indeed fortunate to have Jon Claerbout as an Active Member and it is a real pleasure to see the Medal Award given to one who is achieving so much for exploration geophysics.

     John W. C. Sherwood