In 1968, he drew his first professional comic book story, "The Man Who Murdered Himself", which appeared in "House of Mystery" #179 (cover-dated March–April 1969). He continued to work on a variety of mystery and anthology titles for both DC and, a few years later, its principal rival, Marvel Comics. It was for Marvel's "Chamber of Darkness" and "Tower of Shadows" titles where he was first encouraged to slightly simplify his intricate pen-and-ink drawing, and where his lush brushwork, a hallmark of his comics inking in the 1970s, was first evidenced.