During his almost two decades at Marvel Comics, the legendary Mark Gruenwald wore many hats. He was a writer and editor, and even served as Executive Editor and Editor in Chief of the Avengers and cosmic lines. He had an influential ten-year stint as the writer of "Captain America" and also wrote "Squadron Supreme" and "Quasar." Gruenwald, who would have turned 63 on June 18, passed away in 1996 after suffering a heart attack, the result of an unsuspected congenital heart defect. To celebrate the beloved creator's memory, Marvel.com has an interview with Gruenwald's widow, Catherine Schuller-Gruenwald, wherein she shared stories of the beloved creator -- including how his ashes ended up in a Marvel comic.

"The day Mark passed away, I came back from the hospital and opened up the will and it said he wanted his organs donated and then to be cremated and his ashes put into a comic book," said Schuller-Gruenwald. She recalled how Gruenwald insisted that they create Last Wills and Testaments even before their marriage, as well as take out life insurance policies.

"I told Marvel of his wishes and they agreed to put out a poster of the Marvel Universe with his ashes in it," she continued. "That was printed -- colored by Christie Scheele -- but it was nagging at me that he wasn't in a comic book, [because] that is what he wanted. Marvel decided to reissue 'Squadron Supreme' [as a graphic novel] and I remember him bringing me the entire set of issues when I was laid up healing from hernia surgery. I was flat on my back and a captive audience and enjoyed reading [it]. I can see why it was his favorite because he was able to spread his creative wings; really take a big risk, not be restricted, and branch outside the actual the Marvel Universe and tell a different kind of story than was usually crafted. The fans responded in kind as it was one of his best-selling efforts. [They] were ready for something completely different and it was the right time for him to delve into a new concept. He was so pleased that the fans were with him and got what he was putting forth in [the book]. He was extremely proud of 'Squadron Supreme' and Marvel just knew that's where I should put his ashes. He really threw himself into that work, too, so it made appropriate sense."

Schuller-Gruenwald also recounted how her late husband's sharp memory and fan-turned-pro personality led to the creation of one of Marvel's most beloved '80s publications -- the "Official Handbook of the Marvel Universe."

"[With Mark,] it was memorization facilitated by the key of needing to remember who was who, to keep it all straight and watch how it all dovetailed, and if you love someone you couldn't abuse it or trash it; it had to be taken care of with great attention," said Schuller-Gruenwald. "It was a natural extension of his curiosity mixed with discovery mixed with imagination. He was made for fantasy. He had the capacity to think abstractly, to understand science, astronomy, nature, politics, systems, etc... principles that governed the way things worked. For instance, you had to know physical properties: if a swimming pool had a drain with a plug in it and it was pulled out, the water wouldn't instantly drain out because it was convenient to do so. There was 'real time' and the Marvel Universe had to be true to reality, so learning all the different aspects of what reality was about was very important to Mark and you needed to adhere to the logic exactly. It was fantasy, but not convenient manipulation of the facts. It had to make sense at all times. He assumed the fans were just as into trivia and minutiae and he ultimately created the 'Official Handbook of the Marvel Universe.' He loved the enormity of knowledge, knowing it was a satisfying feeling that enabled you to understand the world, but he also reminded me that everything was either matter or anti-matter."

For more memories of Mark Gruenwald, you can read Marvel.com's entire interview with Catherine Schuller-Gruenwald.