Tom Spurgeon's Comics Reporter reports the death of Paul Cassidy, an early Superman artist and Shuster studio/sweatshop ghost. The site contains links to other online information, including a bio, newspaper obituary and a discussion at the Superman Artists site.
Paul Cassidy, perhaps the first significant ghost artist in American comic books and a contributor to the look and style of Superman, passed away on May 15 at a senior care facility in Milwaukee. He was 94 years old.
Cassidy worked with original Superman artist Joe Shuster from 1938 to 1940, innovating the S-symbol on the cape and providing a generally dynamic variation on Shuster's style. He left the studio in 1940 to find better paying work, and took on stints in editorial and as an artist for encyclopedias and magazines. Cassidy was a teacher for the majority of his professional life, although his family reports he did try to develop his own comics feature, "Fantasy, the Moon Boy."
http://www.comicsreporter.com/index.php/paul_cassidy_1910_2005/