The story that allowed them to use two previous issues of the Justice League of America was having junior Super Friends Marvin White, Wendy Harris and the Wonder Dog are given a tour of JLA headquarters (the Hall Of Justice), as well a little history of the team as well.
Really, its just an opportunity for Toth to draw the Justice League and all its members at the time, as well as a few of the people who helped the team (which include Hawkgirl and Zatanna, as they weren't members at this time...
...likely this and a DC Super-Stars which reprinted some wonderful Zatanna tales are likely the reason she became a member of the JLA).
The treasury also had features on Super Friends animation (which Alex Toth worked on, providing model sheets for the characters.....highlighting the basics needed, which worked well for animation...).
Black Canary series in Adventure Comics!
mystery villain of the piece, and the other needs covering in the future!
A book collection, and artist, that had a lifelong effect on this old comic reader!