Of course the story was credited to Bob Kane, the artist who had brought Batman to DC Comics and tried to take full credit for the character for years. But by that point DC had hired Kane’s original studio team of Bill Finger, Jerry Robinson, and George Roussos, and employed other freelancers as well. The company didn’t keep records from that period, so it’s hard to link particular stories with their creators.
Both Robinson and Roussos reportedly identified “The Isle That Time Forgot” as their work. For other stories and other details, fans have tried to fill in the gaps, but identifying artists by their visual styles is easier than fingering writers.
In DC’s recent reprints and the Grand Comics Database, “The Isle That Time Forgot” is credited to Joseph Greene. That identification appears to rest on the judgment of Martin O’Hearn, apparently based on “comparing textual styles.” That would make this story Greene’s very first published comics script.
However, in 2002 writer Alvin Schwartz has queried whether some of the Batman stories from that period credited to Greene should really be credited to himself. He definitely wrote for DC at the time, couldn’t recall hearing of Joseph Greene, and spotted some details he didn’t think any other writer (except his own erstwhile writing partner Charley Greene) could have come up with.
Complicating matters, other sources say that Greene later wrote under Grosset’s in-house pen name of “Alvin Schwartz.” As a man actually named Alvin Schwartz, Alvin Schwartz was surprised by that. He was more aware than anybody how mid-century American publishing wanted him to use a name more like, well, “Bob Kane” (born Robert Kahn).
But Schwartz also notes that comics historians defending his place in the early comics industry have credited him with stories he never wrote. It’s all very tangled, and if all we have to go on is subjective judgments of “textual styles,” we must learn to live with uncertainty.