Hammer was best known for his 1993 book Reengineering the Corporation (which led to several other reengineering books). I wasn't a fan of his work. In fact, critic and opponent are probably the right terms. I've questioned and challenged his concepts in several of my articles, and even wrote one titled Hammering Hammer.
But, in my introduction to that article, I point out "Dr. Hammer is a nice guy. We corresponded via email as I wrote this piece, and he was both thoughtful and generous."
I hardly ever agreed with Dr. Hammer, but I had to respect his accomplishments and influence. I also deeply respected his humanity and generosity. There was really no reason for him to personally answer my email queries, but he did. I still think that was pretty cool, and I am saddened by this loss.