Mjolnir's Greatest Hits!
This is an adequate intro to the backstory behind Thor - from his young days playing with Sif and Loki to his banishment, on to the events of Journey Into Mystery #83 where Dr. Blake becomes Thor once again. But this comic reads more like a synopsis than a story in itself. Other writers have taken the time to re-craft a hero's origin story as a cohesive whole. This skips through highlights of Thor's early life like a 'greatest hits' album - and like a greatest hits album, it's good at summarizing a career, but takes the individual 'hits' out of the context of the original albums (or in this case comics) that created them - giving the listener (or in this case reader) an incomplete picture.
If you've never read stories like Tales of Asgard, Journey Into Mystery #83, Son of Asgard, or Thor: Man of War, and really have no idea who Thor is or what Mjolnir is - then this comic is for you.
Others can safely skip it.