Charles “Chuck” Geschke, a co-founder of Adobe who helped develop the PDF, has died at age 81, the company said in a statement. ”As co-founders of Adobe, Chuck and John Warnock developed groundbreaking software that has revolutionized how people create and communicate,” Narayen said. via Technology and News Today https://www.theverge.com/2021/4/18/22390452/charles-geschke-cofounder-adobe-inventor-pdf-obituary