Michael E. Grost notes:
Kandor is an entire Kryptonian city that the villain Brainiac shrunk to microscopic size and put in a bottle, a wonderfully poetic concept.
The Superman family of comics eventually developed a series of stories
about Kandor. This 3-part story is one of the key
tales. In it, Superman and Jimmy Olsen first adopt their Kandorian secret
identities of Nightwing and Flamebird; modeled after Batman and
The new costumes they wear, created by legendary Superman artist Curt Swan, are especially cool looking.
Here Hamilton pursues a favorite theme: characters taking on roles and locations belonging to others. Superman and Jimmy take on the careers of Batman and Robin, while also moving to the unfamiliar landscape of Kandor.
The story shows the complex politics that often operate in Kryptonian society. Oddly enough, the Superman comics rarely showed political activity on Earth, regarding this as propagandistic (according to the letter columns of the magazines) but often included political events on Krypton. These political events were somewhat in the tradition of the civics lessons that were popular in all media in the 1950s, but here they are a bit more subtle and complex. Superman is subject to the lynch hysteria that often gripped crowds in 1950s works. However, Krypton is an advanced society and it is deeply civilized, even in the grip of political fevers. The scene in which the Kandorian leader describes his view of relations between Kandorians and Earthlings is especially humane, and especially poignant for it.