This is a story about an ancient manuscript found by two men on a camping trip. The manuscript actually is the story. I'm not going into the plot itself as the description already does that, but I did want to mention a few things.
The story was a bit slow to start out, and there was a long sort of boring out of body experience. Even though I found this part a bit long winded, I can see the seeds of Lovecraft's Cthulhu mythos within.(Lovecraft has said that William Hope Hodgson was a big influence on him). After the protagonist returns to his body things go bat-crap crazy. There are some phenomenal scary scenes and wild things going on.
Then, another long interval (another OOB experience?) that was just weird. I enjoyed this section because it really delves into space. The amount of knowledge displayed by this author about our solar system and how it works is quite amazing since this book was written in the early 1900s.
All in all though, I enjoyed this book. I would recommend it to anyone interested in Lovecraft.