This reprints the two-part Green Arrow story from ADVENTURE COMICS #252 / #253 (1958), editing out the splash page of the second story.
High goofball fun in this one, as the city is attacked by mystriously appearing giant arrows. Of course, Green Arrow and Speedy investigate, since someone is taking their gimmick, eventually finding themselves drawn into an alien dimension.
That bit with GA worrying about never seeing his adoring crowds of kids when he goes to flog the Green Arrow Arrow Kit cracks me up. Also, that's a great alien world.
Anyway, very neat stuff, although of course more readily available in the collection DC did a few years ago.