from William Cohen

I met Sam when he was a graduate student, and worked for a summer at Whizbang Labs, where he impressed everyone, immediately - not only with his smarts and his creativity but with the enthusiasm he brought to everything. Subsequently I've followed his work, read his papers, heard his talks, talked to him at conferences, and worked with him on ICML 2008, where he did an outstanding job as co-program chair when I was general chair. I remember him calling in to biweekly west coast-east coast-Europe meetings at 6:30am his time to help keep the conference coordinated. He was always generous with his time and advice, as well as an absolute pleasure to work with and be around, and a really brilliant and insightful scholar.

There are many smart people in machine learning, but Sam was always special. Some people want to explain things to you to impress you, or intimidate you; some people because they don't know what else to say; some people because of some obscure feeling that it's good for their career. As soon as Sam started talking you could feel why - it wasn't just that he wanted to share his ideas and insights, he also wanted to draw you in and make you part of it. It was a very infectious enthusiasm - it wasn't that he *wanted* you to be part of it, it was that you just *were* part of it - of course! - as soon as he started talking to you. I'm really going to miss that, and I feel sad for the hundreds or thousands of people that have read his work, and maybe caught a tiny glimpse of that welcoming joy and enthusiasm, but never got a chance to be drawn in that way.

I didn't know Sam as well as I would have liked, and I feel a little that I don't deserve to feel this way - compared to his wife and family the loss felt by a sometime colleague is slight. But his death is a real loss, to me and to many others around the world. He will be sorely missed.