In certain ways, the Sixties were a simpler time. Sure, there were things like Vietnam, the civil rights movement and assorted assassinations to make things complicated, but at least with comic books, it was a gentler era. Although the storytelling might have been constrained by the Comics Code, there were still the opportunities to tell good tales. Stan Lee, one of the principal creative forces of the period, put together a lot of good stories. Unfortunately, while The Mighty Thor is not bad, it is also not Lee's best writing of the period.
The Essential Thor #1 covers the earliest Thor stories, back in the days when the magazine was officially named Journey into Mystery. Donald Blake, a vacationing doctor, stumbles upon a stick that, when struck against the ground, transforms him into the god Thor. Within the issues covered, Thor battles such adversaries as the Cobra, Mr. Hyde, the Enchantress, the Executioner and assorted aliens, but his chief adversary is his step-brother, Loki. In addition to the main stories, we are also provided tales of the Norse Gods in the land of Asgard.
While plot-wise, these stories are all decent, they suffer from characters who are relatively bland or ill-defined. I've noticed that the Lee's strongest writing in this era is with the Fantastic Four and Spiderman, where not only are the characters more interesting, but there is a decent supporting cast as well. Here, there are few supporting characters. Love interest Jane Foster is a stereotypical comic book woman of the era; she pines after Thor, faints a lot and is in constant danger. Outside of villains, the only other recurring character of note is Odin, Thor's very powerful father. Odin's behavior is erratic; although described as having great wisdom, he is constantly being duped by Loki.
The character of Thor himself is problematic. While it is clear that Thor and Blake share the same identity (this is not a Jekyll-and-Hyde thing), it is rather hazy as to who is the true version: is it Don Blake, who (like Spiderman), came across a super power, or is it Thor, who merely adopts Blake as a mild-mannered alter ego (like the early Superman disguising himself as Clark Kent)? This is rather inconsistently dealt with, and in fact, there are no real answers within this volume.
I know that I may be overanalyzing this material; after all, these are just comics, aren't they? Yet, I can compare this to other works of the same time (like the previously mentioned FF and Spiderman) and find this to be an inferior work: not bad, but not great: a high three-stars at best. While many will find this entertaining, I cannot recommend this as a first choice in the Essentials series. Instead, I would look elsewhere and come to this book later.