This is kind of a confusing issue to index. It features 1-2 page excerpts of various future issues/story arcs of Legends of the Dark Knight (including two that were never published, and two 'pinups'.) They have been worked into a story by Archie Goodwin and Vince Giarrano which is original to this issue.
The table of contents at the end of the issue can be misread, and might lead you to believe more authors contributed to the issue than have actually done so. The credits for the preview artworks also state the authors of the issues being excerpted. They did not contribute any dialog, narration or other text to this issue. Potentially, some provided storytelling direction for the artists to follow, and are listed below for that reason. Archie Goodwin is the sole author of this issue's story. His script isn't limited to the pages illustrated by Giarrano, and it continues on all the preview pages as well.