Remember those awesome days when crossing from one dimensional plane to another was as easy as turning a page? I miss those days. At times the cross-over stories were bat-shit crazy, and that was half the fun. Check out Dave’s Comic Heroes Blog for some in depth detail on the Heroes of Quality Comics, and how they ended up calling on the JLA to help them in their struggle against nazi scum.
You can find this issue of the classic JLA at Comixology.