Actually, to be a bit more concise, John Warnock was really the “inventor” of PDF, what was originally called The Camelot Project at Adobe (I've attached John Warnock's original document outlining the concepts). That having been said, if it wasn't for Chuck's unyielding encouragement and support (despite many naysayers both externally and even within Adobe), PDF and Acrobat would never have been.
As someone who was honored to work at Adobe while Chuck was actively managing the company with John, I can attest to how remarkable both Chuck and John were in both technical excellence and ethically managing a company and supporting their teams in an industry that is more often noted for flamboyant company founders and executives who are more into themselves than anything else.
- Dov