Paul Cassidy, who was among Joe Shuster's first assistants on the Superman comic books and strip, has passed away at the age of 94. Cassidy spent most of his career as an art teacher but from around 1938 to 1940, he worked in Cleveland for the Siegel and Shuster shop, helping Joe to produce an ever-growing volume of stories and covers featuring their new creation. Scholars have argued over which work from this period is Cassidy's and which is Shuster's, but it would appear that many stories were done as follows: Shuster would do a rough layout of the pages, then Cassidy would tighten up the pencil art on the main figures. Then Shuster would ink main figures or, at least, heads. Finally, the page would be completed by Cassidy. The two Action Comics covers shown above are believed to be all or mostly all Cassidy's work, and he is said to have contributed several enduring refinements to the famous Superman costume and design.
Later Shuster employees — and there were many — had to deal with the fact that Joe was losing his eyesight. But Cassidy was around when Joe could still draw, so he assisted more than he ghosted. He left the job in 1940 and never ventured back into comics. This article tells more about his career.