This is Giant Superman 21, published by Mimosa (SA Magazine Co) +/- 1963-1964.
It reprints the cover and stories from DC Comics' Action Comics 295 (1962):
"Superman Goes Wild"
Supergirl: "The Girl with the X-Ray Mind"
Also reprinted is this story from DC Comics' Adventure Comics 250 (1958):
Superboy: "The Imposter from the Year 2958"
Also reprinted is this story from DC Comics' Adventure Comics 249 (1958):
Green Arrow: "The Man who hated Arrows"
48pages, glossy colour cover, black and white newsprint interior.
Here is the cover of issue 21 and DC Comics' original cover: