I am sorry to see that Bill Butterfield has died, depriving his firm, Hausfeld LLP, and the wider eDiscovery world, of a highly-respected and well-liked speaker and educator.
I did not know him well, but he is one of those who made me welcome in the US eDiscovery scene from my earliest forays across the Atlantic.
Whenever we met, he suggested that we try and do something together but, as with so many such ideas, it never came to pass. I was sorry about that before his death, and even more sorry now.
The Sedona Conference has a tribute to him and there is an article here from Legaltech News.