This is The Atom 1, published by Mimosa (SA Magazine Co) +/- 1963-1964.
It reprints the cover and the following 2 stories from DC Comics' The Atom 8 (1963):
"Lockup in the Lethal Lightbulb!"
"The Purloined Miniatures"
Also reprinted is the following story from DC Comics' House of Mystery 37 (1955):
"The Modern Nostradamus"
32 pages, colour cover, black-and-white interior pages (259x179mm).
Here is the cover of issue 1 and DC Comics' original cover: