I worked with Mark for several years, I worked on the Master Edition of the Marvel Universe Handbook with him for its final year, I edited the SQUADRON SUPREME collection into which his ashes were mixed, and the “temporary container” that held them still remains in my office. I can’t say that he was a close friend or anything, not in the way that a number of other people were, but sure, I learned plenty from him. He in his period and I in mine handle the needs of continuity a bit differently, though.