(written from a Production point of view)
He broke into the industry with Harvey Comics as a letterer, but quickly transferred to the art production department as he was a better artist then letterer. While there, he worked on a variety of books including Richie Rich and Caspar the Friendly Ghost. While there, his main editor was Sid Jacobson.
Once Harvey Comics folded in the early 1980s, he moved on and worked for DC and Marvel Comics on titles such as Green Lantern, Wonder Woman, Flash, Arak, Son of Thunder, Amethyst, Princess of Gemworld, and Doom 2099, and Spider-Man. During this time period, he also worked on the US Star Trek comic strip, where he was the original primary artist on the 17th story arc, "Goodbye to Spock".
Since meeting Jacobson, the two men became began collaborating together including a graphic novel version of the 9/11 Commission Report titled "The 9/11 Report: A Graphic Adaptation". They followed this up with "After 9/11: America's War on Terror". Further collaborations included graphic novel biographies of Ché Guevara and Anne Frank.