I consider Dagon one of Lovecraft's best early works, particularly as it presages many of the concepts seen in later works like The Call of Cthulhu and The Shadow Over Innsmouth; to the point that some scholars consider the former simply an extensive rewriting of Dagon.
Because of its very short length and the fact it covers so many of Lovecraft's major themes I consider this one of the best stories to use as an introduction to his canon.
This is part two in a diptych of the story Dagon, the other half to be viewed here.
...And the faux-Amazing Stories cover version of it. Along with the wear I also warped the image a bit, as if they poorly copied it for the cover. It's actually erroneous as Dagon as a story was never published in AS, but in the fanzine, The Vagrant. Unfortunately I couldn't find an image of The Vagrant online, so I had to make do...