He wasn’t as well-known to the general public like Jack Kirby, Neal Adams or Todd McFarlane but most comic-book readers/fans/aficionados recognize his name. Gene worked for both DC and Marvel drawing key characters: Batman, Daredevil, Wonder Woman; and sometimes the obscure: Howard the Duck. His style tended to gravitate toward the dark, brooding, Horror material; hence he did numerous comics starring Dracula or somebody who could withstand a copyright suit.
The man was a prolific workaholic. Despite failing health, many sites report how he continued to keep working and make appearances. He will be missed since Gene was a key participant in the Silver Age.