A science fiction novella from one of the greatest scientists of the 17th century. Well worth a look despite my three star rating

As proto-scifi, Lucian's "True History" was earlier, and more entertaining.
As said by others, Somnium is of historical importance only. Go for Lucian instead.

I’m a bit confused after reading this.

I can't believe I finally finished this! I lost access to it for a really long time. This was one of the toughest things I've ever read. The actual story is only about 15 pages! The entire other 215 plus pages are notes, appendices and notes on the original notes. I read them all. I'm not sure why it was analyzed quite so much (everything, even his extended family was discussed).

About the 15 page story though, the astronomy stuff in the middle went on and on but I appreciated the beginning and end of the story. I laughed when the boy and his mom covered their heads with their clothes, and then it make sense at the end when he returned to himself and found his head covered by the pillow! The Dream...

Half of this is a story of an Icelandic boy who accidentally becomes Tycho Brahe's apprentice, and his mother who talks to daemons from the moon. The other half is pretty much an astronomical description of the sky and the movement of its bodies as seen from the moon. I'm positively sold!

It's kind of difficult to rate this book. The overall imagination, especially given this book was written in 1608, is astounding. Stories about traveling to the moon already circulated at the time, but Kepler generously butters his story with astrophysical and astronomical descriptions which, unfortunately, make it quite a tedious read. But is nonetheless a supreme work of imagination. It was the Daemon inhabitants of the moon and the fauna and flora I was really looking forward to, but that only takes up a couple of pages at the end. The story also ends abruptly which may be because Kepler never really finished it. Overall this is an important read if you are interested in the origines of sci-fi. I also think it's interesting to see how space travel was imagined in the distant past.

El prólogo a cargo de Francisco Socas de la edición de la Universidad de Huelva me parece, hasta el momento, insuperable.

incredibly brief and dry to the point where parts of it read like a physics textbook but contains what is possibly the first speculative creations of alien worlds and life used in a non-satirical sense

Meh. Just read the Wikipedia article.