It is with great sadness that I announce that my longtime friend and collaborator, Dietmar Schumacher, died on Wednesday September 17, 2014, of a massive stroke. It was in 1971, when he took up his position at Acadia University, that he left a note on my office door introducing himself and suggesting we meet to discuss category theory. We did and that was the start of our long collaboration. We also started, in 1972, the category seminar which still runs today, 42 years later. For many years he would drive the 100 kms from Wolfville every week to attend the seminar, and drive back afterwards. He would sometimes speak in the seminar or, if not, stimulated discussion with his penetrating questions. The last few years, he came less often as he found the drive tiring, but invariably he would read up on the topic of the week and always emailed me a question or two about it. He kept up his interest in category theory until the end. He came to the first seminar this year, just two weeks ago, looking strong and fit as ever. We'll miss his wry sense of humour. His way of apologizing for some little thing, and then apologizing for apologizing. Our thoughts are with his family at this difficult time. Bob